Reflective type color liquid crystal device and an electronic apparatus using this

ABSTRACT

A liquid crystal device includes a pair of substrates and a liquid crystal layer between the pair of substrates. In addition, the device includes a plurality of dots capable of independently applying voltage to the liquid crystal layer, each dot having a dot area that includes a first section and a second section. A color filter is arranged in the first section of at least one of the dots. A substantially transparent area is arranged in the at least one of the dots in the second section where the color filter is not arranged.

This is a Divisional of U.S. patent application Ser. No. 09/671,354filed Sep. 27, 2000, which is a Divisional of U.S. patent applicationSer. No. 08/809,487 (now U.S. Pat. No. 6,147,728), which is the U.S.National Stage of International Application No. PCT/JP96/01983 filedJul. 17, 1996. The entire disclosure of each of the prior applicationsis hereby incorporated by reference herein in their entireties.

BACKGROUND

1. Field of the Invention

The present invention concerns a reflective type color liquid crystaldevice and an electronic apparatus using this.

2. Prior Art

The display mounted on a portable information terminal first must be lowin power consumption. Consequently, reflective type liquid crystaldevices not requiring backlights are optimal for this purpose.Nevertheless, the conventional reflective type liquid crystal device wasmainly a monochrome display, and a good reflective type color liquidcrystal device is yet to be obtained.

The development of the reflective type color liquid crystal deviceappears to have been started in earnest from the middle of the 1980s.Before that, for example, as in the publication of Japanese Laid-OpenPatent No. 50-80799, it was not recognized that if the backlights of atransmissive type color liquid crystal device were replaced with areflection plate, that was equivalent to saying a reflective type colorliquid crystal device may be possible. Nevertheless, it is clear ifactually test created, but with such a configuration it is dark andunusable. There are three causes: (1) ½ or more of the light is lostwith the filter, (2) ⅔ or more of the light is further lost due to thecolor filter, and (3) the problems of parallax. The problems of parallaxcannot be avoided with the TN (twisted nematic) mode and STN (supertwisted nematic) mode in a transmissive liquid crystal device. Thereason is because, since these modes necessarily use two polarizingplates, as long as the polarizing plates cannot be built into the cell,there occurs a gap that cannot be ignored between the reflective plateand the liquid crystal layer. The problems of parallax mentioned hereare not only the problem of double reflection of the display as was thecase with the conventional reflective type monochrome liquid crystaldevice, but it indicates a problem inherent in the reflective type colorliquid crystal device.

The problems of parallax are explained using drawings. FIGS. 77(a) and(b) are cross section drawings of a reflective type color liquid crystaldevice using either the TN mode or the STN mode. This liquid crystaldevice is composed of an upper polarizing plate 7701, an upper glasssubstrate 7702, a liquid crystal layer 7703, a lower glass substrate7704, a lower polarizing plate 7705, a light reflecting plate 7706, anda red-green-blue (RGB) tricolor filter 7707. Between the upper and lowerglass substrates are additionally present a transparent electrode, anorientation film, and an insulating film, but they are omitted as theyare not needed in explaining the problems of parallax. There are twoproblems of parallax. One of these is the mutual cancellation of thecolors. In FIG. 77(a), the observer 7712 sees the reflected light 7711emanating through the green filter, but this light is a blend of theintroduced light 7713 passing through the red, green, and blue filters,and being scattered and reflected by the light reflecting plate. If thethickness of the lower glass substrate is sufficiently thick incomparison to the pitch of the color filters, the light passing throughany colored filters will blend at equal probabilities. As a matter offact, the light passing a course of red→green→blue, regardless of thewavelength of the light, is absorbed and becomes pitch black with anycolor filter, and only the light passing the course of green→greenremains. Since the same can be said about the reflected light passingthrough a blue and a red filter, it becomes a problem that thebrightness finally ends up ⅓ of that of a white display having noparallax. Another problem is that the color display becomes dark. FIG.77(b) shows the status of a green display. Also, the part having applieda matrix-like hatching on the liquid crystal layer 7703 indicates thatit is in the unlit status (dark status). The introduced light 7713passes through red, green, and blue dots at equal probabilities, and ⅔is absorbed by the red and blue dots being in the off status.Furthermore, after having been scattered and blended by the lightreflection plate, ⅔ is again absorbed by the red and blue dots being inthe off status, and the remainder reaches the observer 7712.Consequently, the green display becomes 1/9 the brightness of a whitedisplay minus the portion absorbed by the green filter, and becomes verydark. The use of the TN mode and the STN mode having such problems ofparallax in a reflective type color liquid crystal device is verydifficult.

Thus, in the past, there have been made attempts to obtain a brightreflective type color liquid crystal device by varying the liquidcrystal mode. For example, in the article by Mr. Tatsuo UCHIDA, et al.(IEEE Transactions on Electron Devices, Vol. ED-33, No. 8, pp. 1207-1211(1986)), the PCGH (phase change guest host) mode not requiring apolarizing plate was used upon having performed a comparison of thebrightness of various liquid crystal modes in FIG. 2 of the report.Also, in the publication of Japanese Laid-Open Patent No. 5-241143, thePDLC (polymer distributed type liquid crystal) mode not requiring apolarizing plate was used in order to realize a reflective type colorliquid crystal device. When a liquid crystal mode not requiring apolarizing plate is used, not only does the absorption of the light dueto the polarizing plate disappear, there is also the benefit of beingable to eliminate fundamentally the problems of parallax by providing areflecting plate next to the liquid crystal layer. Nevertheless, on theother hand, the liquid crystal mode not requiring a polarizing plate hasthe problems that the contrast in general is low, and in particular thePCGH mode has hysteresis in the voltage transmissivity properties andintermediate tone displays are not possible. Also, the liquid crystalmodes adding other substances into the liquid crystals have manyproblems in the aspect of reliability. Consequently, if the TN mode andSTN mode are used, having been used widely from the past and showingsatisfactory results, these have not been surpassed.

Also, there have been performed tests to obtain a bright reflective typecolor display using bright color filters. Generally, the color filtersused in a transmissive type color liquid crystal device have spectralproperties as shown in FIG. 78. The horizontal axis of FIG. 78 is thewavelength of the light, and the vertical axis is the transmissivity.7801 is the spectrum of a red filter, 7802 is the spectrum of a greenfilter, and 7803 is the spectrum of a blue filter. The light that can beseen by a human has individual differences, but it is generally withinthe wavelength range of 380 nm to 780 nm, and in particular, thesensitivity is high within the range from 450 nm to 660 nm. All thecolor filters of FIG. 78 have wavelengths whereby the transmissivitybecomes 10% or less in this range, and most of the light is rendereduseless. Also, if the value having simply averaged the transmissivity inthis range of wavelengths is defined as the average transmissivity, theaverage transmissivity of the red filter was 28%, the green filter was33%, and the blue filter was 30%. For use in a reflective type liquidcrystal device, brighter color filters are required. Thus, in theaforementioned article by Mr. Tatsuo UCHIDA, et al., it was proposedthat by using bicolor filters having mutually complementing colors asshown in FIG. 8 of the report, it is brighter than the case of tricolorfilters. Their spectral properties are shown in FIG. 79. The horizontalaxis of FIG. 79 is the wavelength of the light, and the vertical axis isthe reflectivity. 7901 is the spectrum of a green filter, and 7902 isthe spectrum of a magenta filter. It is necessary to pay attention inthe comparison because the vertical axis is displayed as reflectivity,but still, within the 450 nm to 660 nm wavelength range, both colorfilters have wavelengths whereby the transmissivity becomes 10% or less.The average transmissivity of the green filter was 41% and the magentafilter was 48%. Also, an article by Mr. Seiichi MITSUI, et al. (SID92Digest, pp. 437-440 (1992)) also relates to a reflective type colorliquid crystal device having used the same PCGH mode, but they usebright bicolor color filters such as in FIG. 2 of the report. Thespectral properties are shown in FIG. 80. The horizontal axis of FIG. 80is the wavelength of the light, and the vertical axis is thereflectivity. 8001 is the spectrum of the green filter, and 8002 is thespectrum of the magenta filter. The vertical axis displays reflectivity,but if the square root of the reflectivity at each wavelength ishypothesized as the transmissivity, at least the transmissivity of thegreen filter is smaller than 50% at wavelengths of 470 nm or less. Theaverage transmissivity of the green filter was 68%, and the magentafilter was 67%. In both patent publications, there was no problem ofparallax because a reflective plate is provided in a position near theliquid crystal layer, sandwiching a color filter. Consequently, becausethe light necessarily passes through the color filter two times, it ispossible to secure sufficient coloration even when using such a brightcolor filter. Also, the color filter proposed in FIGS. 2(a), (b), and(c) of the previous publication of Japanese Laid-Open Patent No.5-241143 is made brighter by using the three colors, yellow, cyan,magenta rather than the three colors, red, green, blue filter. Theirspectral properties are shown in FIG. 81. The horizontal axis of FIG. 81is the wavelength, and the vertical axis is the reflectivity. 8101 isthe spectrum of the yellow, 8102 is the spectrum of the cyan filter, and8103 is the spectrum of the magenta filter. The vertical axis isrepresented by reflectivity, and because there are no graduations on theaxis, it is difficult to compare, but undoubtedly, within the range of450 nm to 660 nm, all the color filters have wavelengths whereby thetransmissivity is 10% or less. When roughly estimating the averagetransmissivity, the yellow filter was 0% the cyan filter was about 60%,and the magenta filter was about 50%.

Thus, the struggle of the conventional development of a reflective typecolor liquid crystal device was based on the starting point of trying toobtain a bright display by combining bright liquid crystal modes notusing a polarizing plate and bright color filters. However, despitebeing bright color filters, the use of color filters having wavelengthswhereby the transmissivity in the 450 nm to 660 nm wavelength rangestopped at 10% was common.

The present invention aims to provide a reflective type color liquidcrystal device that can display colors brighter and more brilliant thanthe prior art by using a liquid crystal mode that uses a polarizingplate such as TN mode and STN mode, having great merit while tacklingthe various problems of brightness and parallax, and to provide anelectronic apparatus using this.

DISCLOSURE OF THE INVENTION

In order to solve the problems mentioned above, the present inventioncomprises a pair of substrates having electrodes on the opposing innerfaces and having formed matrix-like dot groups, a liquid crystalsandwiched between said substrates, at least two colors of colorfilters, and at least one polarizing plate. By being configured in thismanner, the reflective type liquid crystal device has the advantages ofhaving a higher contrast and being able to display colors morebrilliantly compared with the conventional reflective type liquidcrystal devices that use a liquid crystal mode not having a polarizingplate.

Also, the invention is characterized by the substrate on the side of thereflective plate among said pair of substrates having a thickness of 200μm or more. More preferably, it is characterized by the substrate on theside of the reflective plate having a thickness of 700 μm or more. Inother words, it is characterized by the thickness of the substrate onthe side of the reflective plate being at least 1.25 times thehorizontal or vertical dot pitch, whichever is the shorter, and morepreferably at least 4 times. By being configured in this manner, it hasthe advantage that a high contrast can be secured due to the parallaxeffect even at the smallest drive surface area ratio. In the past, forexample in the publication of Japanese Laid-Open Patent No. 3-64850, itis proposed to make the thickness of the lower substrate of a reflectivetype monochrome liquid crystal device 300 μm or less. Certainly in areflective type monochrome liquid crystal device it is better to makethe lower substrate as thin as possible from the viewpoint of reducingdouble-images (reflections). Nevertheless, in a reflective type colordisplay, it is desirable to make the dot intervals wider from theviewpoint of making the color display brighter. When making the dotintervals wider, the contrast necessarily decreases, but if the lowersubstrate is thick enough, a high contrast can be secured by thereflective effect of the adjoining pixels.

Also, the invention is characterized by at least one color of said colorfilters having a transmissivity of 50% or more for the light of all thewavelengths in the range of 450 nm to 660 nm. More preferably, it ischaracterized by at least two colors of said color filters having atransmissivity of 50% or more for the light of all the wavelengths inthe range of 450 nm to 660 nm. Further preferably, it is characterizedby all of the color filters having a transmissivity of 50% or more forthe light of all the wavelengths in the range of 450 nm to 660 nm. Mostpreferably, it is characterized by all of the color filters having atransmissivity of 60% or more for the light of all the wavelengths inthe range of 450 nm to 660 nm. To express this in other words, it ischaracterized by all of the color filters having an averagetransmissivity of 70% or more for the light of all the wavelengths inthe range of 450 nm to 660 nm. More preferably, it is characterized byall of the color filters having an average transmissivity of 70% to 90%for the light of all the wavelengths in the range of 450 nm to 660 nm.The transmissivity of the color filters mentioned here does not includethe transmissivity of the glass substrates and the transparentelectrodes, overcoats, and undercoats, and it is the transmissivity ofthe color filter unit. Also, when there is a distribution in the densityof the color filters, or when color filters are provided having dotsonly on a part, the average transmissivity within the dots is made thetransmissivity of the color filters. By being configured in this manner,the reflective type color liquid crystal device has the advantage ofbeing able to display bright colors. In the past, for example in theclaims of the publication of Japanese Laid-Open Patent No. 7-239469, ithas all the color filters having the transmissivity of thelight-transmitting areas at or above 80%, and the transmissivity of thelight-absorbing areas at or below 50%. Also, in its preferred,embodiments, the transmissivity of the light-absorbing areas was only20-30%. With such color filters, if a liquid crystal mode using apolarizing plate is used, the display becomes dark and is not practical.

Also, the invention is characterized by said color filters comprisingthree colors, being a red system, a green system, and a blue system,moreover, either of said red system or said blue system color filtersbeing orange or cyan. However, orange filters are characterized byhaving a transmissivity of 70% for the light in the wavelength range of570 nm to 660 nm, desirably at or above 75%. Also, cyan filters arecharacterized by having a transmissivity of 70% for the light in thewavelength range of 450 nm to 520 nm, desirably at or above 75%. Bybeing configured in this manner, the reflective type color liquidcrystal device has the advantage of being able to display bright whiteand bright colors.

Also, the invention is characterized by said color filters comprisingthree colors, being a red system, a green system, and a blue system,moreover, the smallest transmissivity for the light of the red systemcolor filters in the 450 nm to 660 nm range of wavelengths is smallerthan the smallest transmissivity for the light of the green system colorfilters in the 450 nm to 660 nm range of wavelengths. More preferably,it is characterized by the red system and green system color filtershaving a transmissivity of 50% or more for the light of the 450 nm to660 nm range of wavelengths. By being configured in this manner, thereflective type color liquid crystal device has the advantages of beingable to display bright white having small color tainting, and being ableto display brilliant red. Since red is the most appealing color stimulusfor the human eyes, it is extremely preferable to display by accentingthe red.

Also, the invention is characterized by said color filters beingprovided only on a part of the light polarizable areas within each dot.By being configured in this manner, the reflective type color liquidcrystal device of the present invention has the advantages of being ableto use the color filter fabrication technology as conventionally, andthe color blending due to parallax is smaller. Also, when the colorfilters are provided in the positions between the electrodes and theliquid crystals, it has the advantages of a wide visual angle beingobtained, and the color purity in the intermediate tones being improved.In the past, for example, even in the publication of Japanese Laid-OpenPatent No. 7-62723, it was proposed to provide the color filters on apart of the dots, but these are transmissive type liquid crystaldevices, and moreover, they differ from the present invention from thepoint that they are limited to dyeing color filters, and from the pointthat the area providing the color filters is large, being 67% to 91% ofthe dots. (The expression of the publication of Japanese Laid-OpenPatent No. 7-62723 is “the non-colored area is 10-50% the area of thecolored portion.” Consequently, the area of the colored portion of thedots is 100/150=67% and 100/110=91%.)

Also, the invention is characterized by the layers transparent in thevisible light regions being formed at substantially the same thicknessas said color filters in the areas not having color filters provided insaid light polarizable areas and the areas not light polarizable. Bybeing configured in this manner, the reflective type color liquidcrystal device has the advantage of being capable of a high imagequality display without disturbance of the liquid crystal orientation.

Also, the invention is characterized by said color filters beingprovided only on ¾ of the total number of dots. More preferably, it ischaracterized by the filters being provided only on ⅔ of the totalnumber of dots. By being configured in this manner, it has theadvantages of being capable of a bright display, as well as being ableto display usually brilliant colors by adjusting the brightness wherethere is no color filter when performing display of intermediate tonecolors. Conventionally, formation of one pixel with four dots, beingred, green, blue, and white, has been carried out partially fortransmissive type liquid crystal devices, but it has not been proposedfor reflective type color liquid crystal devices. Particularly withreflective type liquid crystal devices using the TN mode and the STNmode, the problems of parallax cannot be avoided, and it becomes verydark when performing color display, but bright color display is possibleby providing dots not having color filters.

Also, the invention is characterized by said color filters beingarranged such that colors of the neighboring dots are different. Thisindicates the so-called mosaic orientation and triangle orientation, andconversely, the stripe orientation does not enter into this scope. Bybeing configured in this manner, it has the advantage of alleviating thephenomenon of the appearance of the coloration being different accordingto the visual angle, particularly when there is a parallax. In the past,for example in the publication of Japanese Laid-Open Patent No. 8-87009,a vertical stripe arrangement was recommended in claim 6 of thepublication. Also, in the Specification of Japanese Laid-Open Patent No.5-241143, page 6, right column, lines 17-18, it was explained that thereis no theoretical difference between the stripe arrangement and thezigzag arrangement. Also, in FIG. 1 of the article by Mr. Tatsuo UCHIDA,et al. (IEEE Transactions on Electron Devices, Vol. ED-33, No. 8, pp.1207-1211 (1986)), mosaic oriented color filters are used, but this is acase having provided the reflecting electrodes inside the cells, and itdiffers with the present invention in that there is no parallax.

Also, the invention is characterized by said color filters beingprovided on the entirety of the effective display areas. By beingconfigured in this manner, it has the advantage of the display beingclearly visible. “Effective display areas” is defined in the ElectronicIndustry Association of Japan (EIAJ) standard, ED-2511A, as “theeffective areas as the drive display areas and the screens followingthat.” Usually, in transmissive type color displays, the color filtersare provided only on the drive display areas, and on the areas outsidethem are provided black masks made of metal or resin. As a matter offact, in reflective type color displays, metallic black masks cannot beused because they cause glare. Also, resinous black masks increase costsbecause black masks originally were not provided on color filters. Byway of explanation, if nothing is provided outside the drive displayareas, the outsides become brighter, and the drive display areas becomerelatively dark. Thus, it is effective to provide the same color filtersoutside the drive display areas, and preferably with the same pattern.

Also, the invention is characterized by black masks not being providedin the areas outside said dots, but instead are provided color filtershaving the same extent of absorption or smaller than the areas insidethe dots. This configuration implies that overlaying of black masks andcolor filters is not provided outside the required dots. Also, itimplies not that nothing is provided outside the dots, but that colorfilters are provided on a part or the entirety thereof. By beingconfigured in this manner, it has the advantage of a bright displaybeing obtainable. This is because, particularly when there is aparallax, it becomes extremely dark if black masks are provided due tothe brightness of the display being substantially proportional to thesquare of the aperture, and conversely, because the contrast is reducedmarkedly no color filters are provided whatsoever outside the dots. Inthe past, for example in the publication of Japanese Laid-Open PatentNo. 59-198489, color filters are provided only on the pixel electrodes,and nothing is provided outside them. Also, in the publication ofJapanese Laid-Open Patent No. 5-241143, cases having and not havingblack masks are explained, but there is nothing between those.

Also, the invention is characterized by color filters being provided onthe outer surface of the substrate on the side of the reflective plateof said pair of substrates. By being configured in this manner, it hasthe advantage of being able to be provided cheaply. Also, it has theadvantages of the assembly margin being expanded, and the visual anglebeing widened.

Also, the invention is characterized by nonlinear elements beingprovided for each dot on the inner surface of the substrate on the sideof the reflective plate of said pair of substrates. By being configuredin this manner, it has the advantages of needless surface reflectionbeing reduced, and high contrast being obtainable.

Also, the invention is characterized by nonlinear elements beingprovided for each dot on the inner surface of one substrate of said pairof substrates, and these being wired in the direction parallel to theshort edges of the dots. Usually, in a data display intended for a PC,because the dots are usually vertically long, the direction parallel tothe short edges of the dots is horizontal (level). By being configuredin this manner, it has the advantages of the aperture increasing, and abright display being obtainable. This is particularly effective whenblack masks are not provided, and when it is a reflective typeconfiguration having parallax.

Also, the invention is characterized by the drive surface area ratiobeing from 60% to 85%. The drive surface area ratio here is defined asthe percentage occupied by the areas driven by the liquid crystals amongthe areas excluding the non-transparent parts such as the metal wiringand MIM elements among the pixels. By being configured in this manner,it has the advantages of having secured contrast, as well as abright-colored display being obtainable.

Also, the invention is characterized by said reflective plate havingscattering properties such that 80% or more of the light is reflected ina 30° cone centered on its positive direction of reflection when a lightbeam is projected onto it. Preferably, it is characterized by havingscattering properties such that 95% or more of the light is reflected inthe 30° cone. By being configured in this manner, it has the advantageof a bright display being obtainable. In the past, for example in theSpecification of Japanese Laid-Open Patent No. 8-87009, page 6, lines43-44, a reflective plate having a directionality of half-extent 30°.Being half-extent 30°, it is a scattering property such that, calculatedroughly, about 30% of the light is reflected in a 30° cone, and thescattering is too much compared to the invention of the presentinvention. With such a configuration, the display becomes dark andcannot stand to practical use.

Also, the invention is characterized by said liquid crystals beingnematic liquid crystals twisted about 90°, and the two polarizing platesare positioned such that their transmissive axes are perpendicular tothe rubbing directions of the respectively adjacent substrates. This hasapplied the reflective type color liquid crystal device the TN modeproposed in the publication of Japanese Laid-Open Patent No. 51-013666.By being configured in this manner, the reflective type color liquidcrystal device has the advantages of being brighter, having highercontrast, and having a wider visual angle.

Also, the invention is characterized by the product Δnxd of the multiplerefraction Δn of the liquid crystals and the thickness d of the liquidcrystal layer is from 0.34 cm to 0.52 μm. More preferably, it ischaracterized by Δnxd being from 0.40 cm to 0.52 cm. Most preferably, itis characterized by Δnxd being 0.40 cm. By being configured in thismanner, the reflective type color liquid crystal device has theadvantages of being brighter and having a wider visual angle. Theconventional reflective type monochrome liquid crystal device used thesecond minimum condition whereby coloration is slight, that is, is usedthe condition whereby Δnxd was 1 μm-1.3 μm. However, with a reflectivetype color liquid crystal device, there is no need to use the secondminimum condition because slight coloration can be guaranteed by thecolor filters. Also, in the Specification of Japanese Laid-Open PatentNo. 8-87009, page 5, lines 25-29, a condition of Δnxd=0.55 μm was used.However, compared to aspects of the invention, this condition is darker,and moreover the coloration is great.

Also, the invention is characterized by said liquid crystals beingnematic liquid crystals twisted 90° or more, and at least one phasevariation film is placed with the two polarizing plates are oriented. Ifpossible, it is desirable to perform multiple-line simultaneousselective driving according to the method disclosed in the publicationof Japanese Laid-Open Patent No. 6-348230. By being configured in thismanner, it has the advantages of being low-cost and bright.

Also, the invention is characterized by said reflective plate beingprovided between the pair of substrates, and only one polarizing platebeing placed. This has applied to the reflective type color liquidcrystal device the nematic liquid crystals having one polarizing plateproposed in the publication of Japanese Laid-Open Patent No. 3-223715.By being configured in this manner, it has the advantages of beingbright and being able to display colors of high color purity.

Also, the invention is characterized by said reflection plate being amirror face reflection plate, and a scattering plate being provided onthe outer surface of the substrate on the side of the introduced light.By being configured in this manner, it has the advantages of beingbright and being able to display colors of high color purity.

Also, the invention is characterized by the liquid crystals on the metalwiring being oriented in the same manner as the liquid crystals on thepixel portion. By being configured in this manner, it has the advantageof being bright.

Also, the invention is characterized by the display being a normallywhite type. By being configured in this manner, it has the advantage ofbeing bright.

Also, the invention is characterized by one pixel being composed of onebit. By being configured in this manner, it has the advantage of beingable to increase the resolution during monochrome display.

Also, the electronic apparatus of the present invention comprises areflective type color liquid crystal device as the display. By beingconfigured in this manner, the electronic apparatus has the advantagesof being low in power consumption, thin and light-weight, and havinggood visual recognition even when under direct sunlight.

Also, the apparatus is characterized by the display being attached so asto be moveable against the main body so that the peripheral light can bereflected efficiently to the observer. By being configured in thismanner, it has the advantage of a bright display being obtainable.

SUMMARY

The present invention uses a liquid crystal mode having a polarizingplate, and is characterized in that this is combined with color filters.There are numerous LCD modes having polarizing plates, but for thepurpose of the present invention, an LCD mode capable of bright blackand white display is suitable, such as the TN mode proposed in thepublication of Japanese Laid-Open Patent No. 51-013666, the phasevariation plate compensated type STN mode proposed in the publication ofJapanese Laid-Open Patent No. 3-50249, the single polarizing plate typenematic liquid crystal mode proposed in the publication of JapaneseLaid-Open Patent No. 3-223715, the nematic liquid crystal modeperforming doubly stable switching proposed in the publication ofJapanese Laid-Open Patent No. 6-235920, and the like.

A liquid crystal mode having a polarizing plate loses ½ or more of thelight just by the presence of the polarizing plate. Consequently, in areflective type color liquid crystal device, it should be more suitableto use a liquid crystal mode not having a polarizing plate. As a matterof fact, a liquid crystal mode not having a polarizing plate generallyhas low contrast, even when being the PCGH mode or PDLC mode.Consequently, when the pixels are composed of RGB dots, even when forgreen display the green dots are in the bright state and the blue andred pixels are in the dark state, if the contrast is insufficient, theblue and the red get mixed into the green display and the color puritydecreases. As a matter of fact, in a liquid crystal mode having apolarizing plate, such phenomena does not occur because the contrast ishigh. Consequently, if the same color is displayed, it is a liquidcrystal mode having a polarizing plate that can use color filters havinglow color purity. Since filters having low color purity are bright colorfilters, their portions should become bright displays. Also, becausePCGH in particular is a normally black display, the areas between thedots are dark and may not contribute to the brightness, and the lightfrom the visual angles other than the normal line direction of the panelmay be absorbed by the pigment, and despite that a polarizing plate isnot used, only a brightness to the extent of a 20% increase over the TNmode can be achieved. As long as the difference of brightness is to thisextent, it can be overcome easily by the color design of the colorfilters.

Another problem in using a liquid crystal mode having a polarizing plateis the problem of parallax. When only one polarizing plate is used, thisproblem too can be avoided by building the polarizing plate into thecell, but it is unavoidable in the TN mode and STN mode using twopolarizing plates. Regarding parallax, it was already discussed indetail in the paragraphs, “Problems the Invention Tries to Solve,” butthere are two problems. One is the problem of the mutual cancellation ofcolors, and the other is that the color display becomes dark.

The problem of the mutual cancellation of colors, in short, is that ifthe colors of the color filters passed through during introduction andthe colors of the color filters passed through during emission differ,the brightness of a white display becomes ⅓ that of the case of noparallax because cancel each other and become pitch black. Such aproblem occurs due to the use of the color filters alone in thetransmissive type as shown in FIG. 78. If bright color filters are used,there is no turning pitch black even when passing through color filtersof different colors.

Also, the problem of the color display becoming dark, in short, is thatwhen displaying certain single colors, because ⅔ of the entirety of thedots are in the dark state, ⅔ during introduction is absorbed and ⅔ isfurther absorbed during emission, and only 1/9 of the light can be used.This is ⅓ the brightness of the case having no parallax. In order tosolve this, first it is necessary to increase the aperture.Specifically, it takes a means whereby black masks are not providedoutside the dots, MIM having metal wiring only on one side is used, theMIM is wired in the horizontal direction, and STN not requiring metalwiring is used. Moreover, by further reducing the drive surface arearatio, it is made such that an area far smaller than ⅔ the area of theentirety when displaying single colors (for example, about ½) goes intothe dark state. By doing thus, a bright color display is possible evenwhen there is a parallax. The means of making the drive surface arearatio smaller and not providing black masks is connected to thereduction of contrast, but by making the lower substrate thicker, it ispossible to constrain to a minimum the reduction of contrast.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing showing the essential components of the structure ofa reflective type color liquid crystal device in preferred embodiments1-4, 27, 29, and 33 of the present invention.

FIG. 2 is a drawing showing the spectral properties of the color filtersof a reflective type color liquid crystal device in preferred embodiment1 of the present invention.

FIG. 3 is a drawing showing the spectral properties of the color filtersof a reflective type color liquid crystal device in preferredembodiments 2, 3, 5, 23, 29, 31, 32, 34, 36, and 40 of the presentinvention.

FIG. 4 is a drawing having plotted the change of contrast when havingchanged the thickness of the element substrate in a reflective typecolor liquid crystal device in preferred embodiment 3 of the presentinvention.

FIG. 5 is a drawing showing the spectral properties of the color filtersof a reflective type color liquid crystal device in preferred embodiment4 of the present invention.

FIG. 6 is a drawing showing the essential components of the structure ofa reflective type color liquid crystal device in preferred embodiments5, 6, 23, 27, 32, and 40 of the present invention.

FIG. 7 is a drawing showing the spectral properties of the color filtersof a reflective type color liquid crystal device in preferred embodiment6 of the present invention.

FIG. 8 is a drawing showing the essential components of the structure ofa reflective type color liquid crystal device in preferred embodiments7, 9, 24, 27, 28 of the present invention.

FIG. 9 is a drawing showing the spectral properties of the color filtersof a reflective type color liquid crystal device in preferred embodiment7 of the present invention.

FIG. 10 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferredembodiments 8 and 10 of the present invention.

FIG. 11 is a drawing showing the spectral properties of the colorfilters of a reflective type color liquid crystal device in preferredembodiment 8 of the present invention.

FIG. 12 is a drawing showing the spectral properties of the colorfilters of a reflective type color liquid crystal device in preferredembodiments 9, 24, 25, and 26 of the present invention.

FIG. 13 is a drawing showing the spectral properties of the colorfilters of a reflective type color liquid crystal device in preferredembodiment 10 of the present invention.

FIG. 14 is a drawing having plotted the change of average transmissivitywhen having changed the thickness of the color filters in a reflectivetype color liquid crystal device in preferred embodiment 10 of thepresent invention.

FIG. 15 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferredembodiments 11, 12, and 15 of the present invention.

FIG. 16 is a drawing showing the spectral properties of the colorfilters of a reflective type color liquid crystal device in preferredembodiments 11, 21, and 26 of the present invention.

FIG. 17 is a drawing having plotted the change of average transmissivitywhen having changed the percentage of the area providing the colorfilters in a reflective type color liquid crystal device in preferredembodiment 11 of the present invention.

FIG. 18 is a drawing showing the spectral properties of the colorfilters of a reflective type color liquid crystal device in preferredembodiments 12 and 26 of the present invention.

FIG. 19 is a drawing having plotted the change of average transmissivitywhen having changed the percentage of the area providing the colorfilters in a reflective type color liquid crystal device in preferredembodiment 12 of the present invention.

FIG. 20 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferredembodiments 13 and 15 of the present invention.

FIG. 21 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferredembodiments 14 and 15 of the present invention.

FIG. 22 is a drawing showing the voltage reflectivity properties of thecolor filters of a reflective type color liquid crystal device inpreferred embodiment 15 of the present invention.

FIG. 23 is a drawing showing the essential components of the structureof the color filter substrate of a reflective type color liquid crystaldevice in preferred embodiment 16 of the present invention.

FIG. 24 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment16 of the present invention.

FIG. 25 is a drawing showing the spectral properties of the colorfilters of a reflective type color liquid crystal device in preferredembodiment 16 of the present invention.

FIG. 26 is drawing showing the average spectral properties in one dot ofthe color filters of a reflective type color liquid crystal device inpreferred embodiments 16 and 17 of the present invention.

FIG. 27 is a drawing showing the structure of the color filter substrateof a reflective type color liquid crystal device in the comparativeexample mentioned in preferred embodiment 16 of the present invention.

FIG. 28 is a drawing showing the essential components of the structureof the color filter substrate of a reflective type color liquid crystaldevice in preferred embodiment 17 of the present invention.

FIG. 29 is a drawing showing the spectral properties of the colorfilters of a reflective type color liquid crystal device in preferredembodiment 17 of the present invention.

FIG. 30 is a drawing showing the spectral properties of the colorfilters of a reflective type color liquid crystal device in preferredembodiment 17 of the present invention.

FIG. 31 is a drawing showing the spectral properties of the colorfilters of a reflective type color liquid crystal device in preferredembodiment 17 of the present invention.

FIG. 32 is a drawing showing the placement of the color filters of areflective type color liquid crystal device in preferred embodiment 18of the present invention.

FIG. 33 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment21 of the present invention.

FIG. 34 is a drawing showing the placement of the color filters of areflective type color liquid crystal device in preferred embodiment 21of the present invention.

FIG. 35 is a drawing showing the placement of the color filters of areflective type color liquid crystal device in preferred embodiment 21of the present invention.

FIG. 36 is a drawing showing the placement of the color filters of areflective type color liquid crystal device in preferred embodiment 21of the present invention.

FIG. 37 is a drawing showing an outline of the structure of a reflectivetype color liquid crystal device in preferred embodiment 22 of thepresent invention.

FIG. 38 is a drawing showing the placement of the color filters of areflective type color liquid crystal device in preferred embodiment 23of the present invention.

FIG. 39 is a drawing showing the placement of the color filters of areflective type color liquid crystal device in preferred embodiment 24of the present invention.

FIG. 40 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment25 of the present invention.

FIG. 41 is a drawing showing the placement of the color filters of areflective type color liquid crystal device in preferred embodiment 25of the present invention.

FIG. 42 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment26 of the present invention.

FIG. 43 is a drawing showing the wiring method of the MIM element of areflective type color liquid crystal device in preferred embodiment 28of the present invention.

FIG. 44 is a drawing showing the wiring method of the MIM element of areflective type color liquid crystal device of the comparative examplementioned in preferred embodiment 28 of the present invention.

FIG. 45 is a drawing having plotted the change of contrast andreflectivity when having changed the drive area in a reflective typecolor liquid crystal device in preferred embodiment 29 of the presentinvention.

FIG. 46 is a drawing showing the scattering properties of the reflectiveplate of a reflective type color liquid crystal device in preferredembodiment 30 of the present invention.

FIG. 47 is a drawing showing the scattering properties of the reflectiveplate of a reflective type color liquid crystal device in preferredembodiment 30 of the present invention.

FIG. 48 is a drawing having plotted the brightness and contrast ratiowhen having changed the percentage of light reflected inside a 30° conein a reflective type color liquid crystal device in preferred embodiment30 of the present invention.

FIG. 49 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment31 of the present invention.

FIG. 50 is a drawing showing the relationships of each axis of areflective type color liquid crystal device in preferred embodiments 32and 33 of the present invention.

FIG. 51 is a drawing having plotted the change of reflectivity of thewhite display when having changed the Δnxd of the liquid crystal cellsof a reflective type color liquid crystal device in preferred embodiment33 of the present invention.

FIG. 52 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment34 of the present invention.

FIG. 53 is a drawing showing the relationships of each axis of areflective type color liquid crystal device in preferred embodiments 34and 35 of the present invention.

FIG. 54 is a drawing showing the spectral properties of the colorfilters of a reflective type color liquid crystal device in preferredembodiment 35 of the present invention.

FIG. 55 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment35 of the present invention.

FIG. 56 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment36 of the present invention.

FIG. 57 is a drawing showing the relationships of each axis of areflective type color liquid crystal device in preferred embodiment 36of the present invention.

FIG. 58 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment36 of the present invention.

FIG. 59 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferredembodiments 37 and 39 of the present invention.

FIG. 60 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment37 of the present invention.

FIG. 61 is a drawing showing the relationships of each axis of areflective type color liquid crystal device in preferred embodiments 37and 38 of the present invention.

FIG. 62 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment37 of the present invention.

FIG. 63 is a drawing showing the relationships of each axis of areflective type color liquid crystal device in preferred embodiments 37and 38 of the present invention.

FIG. 64 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment37 of the present invention.

FIG. 65 is a drawing showing the scattering properties of the scatteringplate of a reflective type color liquid crystal device in preferredembodiment 37 of the present invention.

FIG. 66 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment37 of the present invention.

FIG. 67 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment37 of the present invention.

FIG. 68 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment37 of the present invention.

FIG. 69 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment37 of the present invention.

FIG. 70 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment38 of the present invention.

FIG. 71 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment38 of the present invention.

FIG. 72 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in preferred embodiment38 of the present invention.

FIG. 73 is a drawing showing the voltage transmissivity of a reflectivetype color liquid crystal device in preferred embodiment 39 of thepresent invention.

FIG. 74 is a drawing showing an example of the display method of areflective type color liquid crystal device in preferred embodiment 40of the present invention.

FIG. 75 is a drawing showing an example of an electronic apparatus usinga reflective type color liquid crystal device in preferred embodiment 41of the present invention.

FIG. 76 is a drawing showing an example of an electronic apparatus usinga reflective type color liquid crystal device in preferred embodiment 41of the present invention.

FIG. 77 is a drawing explaining the problems of parallax inherent inreflective type color liquid crystal devices.

FIG. 78 is a drawing showing the spectral properties of the colorfilters of a conventional transmissive type color liquid crystal device.

FIG. 79 is a drawing showing the spectral properties of the colorfilters proposed in FIG. 8 of the article by Mr. Tatsuo UCHIDA, et al.(IEEE Transactions on Electron Devices, Vol. ED-33, No. 8, pp. 1207-1211(1986)).

FIG. 80 is a drawing showing the spectral properties of the colorfilters proposed in FIG. 2 of the article by Mr. Seiichi MITTSUI, et al.(SID92 Digest, pp. 437-440 (1992)).

FIG. 81 is a drawing showing the spectral properties of the colorfilters proposed in FIG. 2(a), (b), and (c) of the publication ofJapanese Laid-Open Patent No. 5-241143.

DETAILED DESCRIPTION OF EMBODIMENTS

The present invention is explained below based on the drawings.

Preferred Embodiment 1

FIG. 1 is a drawing showing the essential components of the structure ofa reflective type color liquid crystal device according to aspects ofthe present invention. First the configuration is explained. 101 is theupper polarizing plate, 102 is the opposing substrate, 103 is the liquidcrystals, 104 is the element substrate, 105 is the lower polarizingplate, and 106 is the scattering reflective plate. On the opposingsubstrate 102 are provided the color filters 107 and the opposingelectrodes (scanning wires) 108, and on the element substrate 104 areprovided the signal wires 109, the pixel electrodes 110, and the MIMelements 111. Here, 101 and 102, 104 and 105, and 105 and 106 are drawnseparated from each other, but this is in order to clarify the drawing,and in actuality they are adhered with glue. Also, the space between theopposing substrate 102 and the element substrate 104 is also drawnwidely separated, but this is for the same reason, and in actualitythere is only a gap of several μm to several tens of μm. Also, becauseFIG. 1 shows the essential components of a reflective type color liquidcrystal device, only 3×3=9 dots are illustrated, but the presentpreferred embodiment has a higher number of dots than that, and it mayhave 480×640=307,200 dots or more.

The opposing electrodes 108 and the pixel electrodes 110 are composed oftransparent ITO, and the signal wires are formed with metallic Ta. TheMIM elements are of a structure having sandwiched an insulating filmTa205 with metallic Ta and metallic Cr. The liquid crystals 103 arenematic liquid crystals twisted 90°, and the upper and lower polarizingplates have their polarizing axes perpendicular to each other. This isthe common TN mode configuration. Also, the color filters 107 arecomposed of the two colors, red (“R” in the drawing) and cyan (“C” inthe drawing), being in a mutually complementary relationship, and theyare arranged in stripes.

FIG. 2 is a drawing showing the spectral properties of the color filters107. The horizontal axis of FIG. 2 is the light wavelength, the verticalaxis is the transmissivity, 201 shows the spectrum of the red filter,and 202 shows the spectrum of the cyan filter. The spectral measurementwas performed for the opposing substrate unit using a microspectrometer,and the transmissivity was corrected to 100% by adding the glasssubstrates, the transmissive electrodes, and if present, the overcoatsand undercoats. Consequently, they are the measurements of the spectralproperties of the color filter units. All the properties of the colorfilters below were measured using this method. Also, the transmissivityin the claims is defined as the values measured by this method. Both thered filter and the cyan filter always show transmissivities of 30% ormore within the wavelength range of 450 nm to 660 nm. Also, the averagetransmissivity within the same wavelength range was 52% for the redfilter and 66% for the cyan filter. Since they are such extremelylightly colored color filters, it would be more correct to designate the“red” as “pink,” but in order to avoid confusion, they are unified belowby the expressions of pure colors.

The reflective type color liquid crystal device made in the above mannerhad a reflectivity of 24% and a contrast ratio of 1:15 during whitedisplay, it was capable of displaying the four colors, white, red, cyan,and black, the color of the red display was x=0.39, y=0.32, and thecolor of the cyan display was x=0.28, y=0.31. This is about 60 percentthe brightness of the conventional reflective type monochrome liquidcrystal device, an equivalent contrast ratio, and they are propertiessufficient to be capable of use under normal indoor illumination orduring the daytime outside.

A reflective type color liquid crystal device having color filtersshowing transmissivities not meeting 30% within even one part of therange of 450 nm to 660 nm cannot stand to normal use either for thereason that the display is dark and special illumination is necessary,or the white balance goes awry and white cannot be displayed.

In Preferred Embodiment 1, a structure was taken having providedtransparent electrodes on the color filters, but there is no particularobstruction to providing the color filters on top of the transparentelectrodes. Also, MIM elements were used as the active elements, butthis was because they are useful in increasing the aperture, but if theaperture is the same, there is no change in the effect of the presentinvention even when using TFT elements.

Preferred Embodiment 2

FIG. 3 is a drawing showing the spectral properties of the color filtersof the reflective type color liquid crystal device according to aspectsof the present invention. The configuration of Preferred Embodiment 2 issimilar to that of Preferred Embodiment 1 shown in FIG. 1, and colorfilters consisting of the two colors, red and cyan, still are provided.The horizontal axis of FIG. 2 is the light wavelength, the horizontalaxis is the transmissivity, 301 shows the spectrum of the red filter,and 302 shows the spectrum of the cyan filter. Both colored colorfilters have transmissivities of 50% or more within the wavelength rangeof 450 nm to 660 nm. Also, the average transmissivity within the samewavelength range was 70% for the red filter and 78% for the cyan filter.

This reflective type color liquid crystal device had a reflectivity of30% and a contrast ratio of 1:15 during white display, it was capable ofdisplaying the four colors, white, red, cyan, and black, the color ofthe red display was x=0.34, y=0.32, and the color of the cyan displaywas x=0.29, y=0.31. This is about 70 percent the brightness of theconventional reflective type monochrome liquid crystal device, and anequivalent contrast ratio.

Thus, if at least one color of the color filters has a transmissivity of50% or more for the light of all the wavelengths within the range of 450nm to 660 nm, a bright reflective type color liquid crystal device canbe obtained being usable under the substantially identical environmentsas the conventional reflective type monochrome liquid crystal device.When the color filters are constituted by two colors as in the presentpreferred embodiment, if one of the color filters has a transmissivityof 50% or more for the light of all wavelengths within the range of 450nm to 660 nm, in addition to obtaining a good white balance, the othercolor filter also by necessity becomes such that it has a transmissivityof 50% or more in the same manner. Nevertheless, it is not necessarilyso when using color filters of three colors or more. An example of thatis introduced later in Preferred Embodiment 9.

Preferred Embodiment 3

FIG. 1 is a drawing showing the essential components of the structure ofa reflective type color liquid crystal device according to aspects ofthe present invention. Also, FIG. 2 is a drawing showing the spectralproperties of the color filters. Since the configuration of PreferredEmbodiment 3 is fundamentally identical to the reflective type colorliquid crystal device as defined in Preferred Embodiment 1, explanationof the various symbols is abridged. However, the Δnxd of the liquidcrystals is set to 0.42 cm. Also, the dot pitch was made 160 μmhorizontally and vertically, and the drive surface area ratio was made75%.

In Preferred Embodiment 3, the thicknesses of the lower substrates werechanged variously. FIG. 4 shows the contrast when having changed thethickness of the element substrate 104. The horizontal axis in FIG. 4 isthe thickness of the element substrate 104, the vertical axis is thecontrast, 401 is the aggregation of the points indicating the contrastfor each thickness of the element substrate 104 in Preferred Embodiment3, and 402 is the aggregation of the points indicating the contrast foreach thickness of the element substrate in a comparative example. Thedisplay colors when displaying colors was near x=0.39, y=0.32 for red,and x=0.28, y=0.31.

Since the drive surface area ratio is 75%, when the thickness of theelement substrate is zero, the contrast can only reach at most100/(100−75)=4. As a matter of fact, a good contrast of 1:15 or more wasachieved by the parallax effect, that is, the reflections of theadjacent dots, alleviating the light loss between the dots. Also, aneven higher contrast was obtainable by making the thickness of theelement substrate 700 μm or more.

Because the optimum value of this thickness is in a close relationshipwith the dot pitch, the expressions 200 μm or more and 700 μm or morealso may be expressed as 1.25 times or more the dot pitch of the shorterof either the horizontal or vertical and 4 times or more the same.

Preferred Embodiment 4

FIG. 5 is a drawing showing the spectral properties of the color filtersof a reflective type color liquid crystal device according to aspects ofthe present invention. The configuration of Preferred Embodiment 3 isidentical to that of Preferred Embodiment 1 shown in FIG. 1, and colorfilters consisting of the two colors, red and cyan, still are provided.The horizontal axis of FIG. 5 is the light wavelength, the horizontalaxis is the transmissivity, 501 shows the spectrum of the red filter,and 502 shows the spectrum of the cyan filter. Both colored colorfilters have transmissivities of 60% or more within the wavelength rangeof 450 nm to 660 nm. Also, the average transmissivity within the samewavelength range was 75% for the red filter and 80% for the cyan filter.

This reflective type color liquid crystal device had a reflectivity of31% and a contrast ratio of 1:15 during white display, it was capable ofdisplaying the four colors, white, red, cyan, and black, the color ofthe red display was x=0.33, y=0.33, and the color of the cyan displaywas x=0.30, y=0.31. This is about 80 percent the brightness of theconventional reflective type monochrome liquid crystal device, and anequivalent contrast ratio.

Thus, if both color filters have transmissivities of 60% or more for thelight of all the wavelengths within the range of 450 nm to 660 nm, abright reflective type color liquid crystal device usable withoutobstruction even when fixing an input means such as touch keys on thefront surface of the liquid crystal device. However, if color filtersare used not exceeding an average transmissivity of 90% within the samewavelength range, the display becomes extremely light and discriminationof the colors becomes difficult.

Preferred Embodiment 5

FIG. 6 is a drawing showing the essential elements of the structure of areflective type color liquid crystal device according to aspects of thepresent invention. First the configuration is explained. 601 is theupper polarizing plate, 602 is the opposing substrate, 603 is the liquidcrystals, 604 is the element substrate, 605 is the lower polarizingplate, and 606 is the scattering reflective plate. On the opposingsubstrate 602 are provided the color filters 607 and the opposingelectrodes (scanning wires) 608, and on the element substrate 604 areprovided the signal wires 609, the pixel electrodes 610, and the MIMelements 611.

Here, the color filters 7 are composed of the two colors, red (“R” inthe drawing) and cyan (“C” in the drawing), being in a mutuallycomplementary relationship, and they are arranged in mosaics so as todraw a checkered pattern. If the color filters are arranged in stripesas in FIG. 1, it will have extremely wide visual angle properties up anddown, but it gets an alternating appearance of visual angles havingcoloration and visual angles losing color when moving the visual angleleft and right. This is a phenomenon occurring because there is adistance only in the thickness of the lower substrate (the elementsubstrate in this case) between the liquid crystal and color filterlayers and the reflective plate. When arranged in mosaics so as to drawa checkered pattern as in FIG. 5, it is confirmed by experiment thatsuch a phenomenon can be alleviated somewhat. It was also learned thatthe mixing of colors is good especially when the number of pixels iscomparatively small. It is thought that this is due to the mixing of thevisual angles having coloration and the visual angles losing colors inthe case of mosaic arrangement, and that with at least one eye itappears as colored.

The color filters have the identical spectral properties as FIG. 3 ofPreferred Embodiment 2, and the brightness and contrast ratio were alsothe same extent as Preferred Embodiment 2. Also, here was presented anexample of mosaic arrangement, but if it is an arrangement in which thecolors of the neighboring dots are different, other arrangementsbeginning with a triangle arrangement are also effective.

Preferred Embodiment 6

FIG. 7 is a drawing showing the spectral properties of the color filtersof the reflective type color liquid crystal device according to aspectsof the present invention. The configuration of Preferred Embodiment 2 isidentical to Preferred Embodiment 5 shown in FIG. 6, but color filtersconsisting of the two colors, green and magenta, are provided in placeof the red and cyan. The horizontal axis of FIG. 7 is the lightwavelength, the vertical axis is the transmissivity, 701 shows thespectrum of the green filter, and 702 shows the spectrum of the magentafilter. The color filters of both colors have transmissivities at 50% ormore in the 450 nm to 660 nm wavelength ranges. Also, the averagetransmissivity in the same wavelength ranges is 76% for the green filterand 78% for the magenta filter.

This reflective type color liquid crystal device had a reflectivity of31% and a contrast ratio of 1:17 during white display, it was capable ofdisplaying the four colors, white, green, magenta, and black, the colorof the green display was x=0.31, y=0.35, and the color of the magentadisplay was x=0.32, y=0.29. This is about 80 percent the brightness ofthe conventional reflective type monochrome liquid crystal device, andan equivalent contrast ratio.

As the two colors being in a mutually complementary relationship, otherthan red and cyan, and green and magenta, the combination of blue andyellow can be imagined, but from the standpoint of attractiveness, it ismore desirable that colors of the red system can be displayed such as inthe former two.

Preferred Embodiment 7

FIG. 8 is a drawing showing the essential elements of the structure of areflective type color liquid crystal device according to aspects of thepresent invention. First the configuration is explained. 801 is theupper polarizing plate, 802 is the opposing substrate, 803 is the liquidcrystals, 804 is the element substrate, 805 is the lower polarizingplate, and 806 is the scattering reflective plate. On the opposingsubstrate 802 are provided the color filters 807 and the opposingelectrodes (scanning wires) 808, and on the element substrate 804 areprovided the signal wires 809, the pixel electrodes 810, and the MIMelements 811. On top of the upper polarizing plate is applied a weakantiglare processing for the purpose of suppressing glare of theilluminating light.

Here, the color filters 807 are composed of the three colors, red (“R”in the drawing) green (“G” in the drawing), and blue (“B” in thedrawing), and they are arranged in mosaics as in the drawing.

FIG. 9 is a drawing showing the spectral properties of the color filters807. The horizontal axis of FIG. 9 is the light wavelength, the verticalaxis is the transmissivity, 901 shows the spectrum of the red filter,902 shows the spectrum of the green filter, and 903 shows the spectrumof the blue filter. The color filters of all the colors havetransmissivities at 50% or more in the 450 nm to 660 nm wavelengthranges. Also, the average transmissivity in the same wavelength rangesis 74% for the red filter, 75% for the green filter, and 64% for theblue filter.

The reflective type color liquid crystal device made in the above mannerhad a reflectivity of 28% and a contrast ratio of 1:14 during whitedisplay, it was capable of filtered display, the color of the reddisplay was x=0.39, y=0.32, the color of the green display was x=0.31,y=0.35, and the color of the blue display was x=0.29, y=0.27. This isabout 70 percent the brightness of the conventional reflective typemonochrome liquid crystal device, and an equivalent contrast ratio, andit has properties for enjoying video images without needing specialillumination.

Preferred Embodiment 8

FIG. 10 is a drawing showing the essential elements of the structure ofa reflective type color liquid crystal device according to aspects ofthe present invention. First the configuration is explained. 1001 is theupper polarizing plate, 1002 is the element substrate, 1003 is theliquid crystals, 1004 is the opposing substrate, 1005 is the lowerpolarizing plate, and 1006 is the scattering reflective plate. On theopposing substrate 1004 are provided the opposing electrodes (scanningwires) 1011 and the color filters 1010, and on the element substrate1002 are provided the signal wires 1007, the MIM elements 1008, and thepixel electrodes 1009. The color filters 1010 are the dye scatteringtype, and they consist of the three colors, red (“R” in the drawing),green (“G” in the drawing), and blue (“B” in the drawing).

FIG. 11 is a drawing showing the spectral properties of the colorfilters 1010. The horizontal axis of FIG. 11 is the light wavelength,the vertical axis is the transmissivity, 1101 shows the spectrum of thered filter, 1102 shows the spectrum of the green filter, and 1103 showsthe spectrum of the blue filter. 1101, 1102, and 1103 are all lightcolor filters, but the images displayed with such filters are light. Thevisibility of the red and blue may be particularly low, anddiscrimination of the colors is difficult. Thus, although the tinge ischanged more or less, bright color filters transmitting a broader rangeof wavelengths were used.

When a red filter having lower color purity was used in place of the redfilter, a rather orange-ish but very bright red could be displayed. Thespectrum of this filter is shown in 1111. This filter is characterizedby having a transmissivity of 70% or more, desirably 75% or more, forthe light of the wavelengths in the range of 570 nm to 660 nm. Also,when a blue filter having lower color purity was used in place of theblue filter, a rather cyan-ish but very bright blue could be displayed.This filter is shown in 1114. This filter is characterized by having atransmissivity of 70% or more, desirably 75% or more, for the light ofthe wavelengths in the range of 450 nm to 520 nm. Nevertheless, if suchcolor filters are used, the white display has a tendency toward becomingreddish or bluish. Thus, when using the above color filters, it isdesirable to adjust the color balance by combining a green filter havinga higher color purity. A green filter having a higher color purity isshown in 1112. This filter is characterized by having a transmissivityof 70% or more for the light of the wavelengths in the range of 510 nmto 590 nm.

Preferred Embodiment 9

FIG. 12 is a drawing showing the spectral properties of the colorfilters of a reflective type color liquid crystal device according toaspects of the present invention. The configuration of PreferredEmbodiment 9 is similar to the case of Preferred Embodiment 7 shown inFIG. 8, and color filters consisting of the three colors, red, green,and blue, are still provided. The horizontal axis of FIG. 12 is thelight wavelength, the vertical axis is the transmissivity, 1201 showsthe spectrum of the red filter, 1202 shows the spectrum of the greenfilter, and 1203 shows the spectrum of the blue filter. Here, only thegreen filter has a transmissivity of 50% or more within the wavelengthrange of 450 nm to 660 nm. Also, the lowest transmissivity of the redfilter for the light of the wavelengths in the range of 450 nm to 660 nmis clearly lower in comparison with the blue filter and the greenfilter. By having such a red filter, it is possible to displaybrilliantly the red that appeals most to the human eyes. Also, in theaim of compensate for the deepening of the red, the spectrum 1203 of theblue filter was made nearer to cyan. Therefore, bright colors havinglittle coloration could be displayed.

The reflective type color liquid crystal device made in the above mannerhad a reflectivity of 26% and a contrast ratio of 1:13 during whitedisplay, it was capable of filtered display, the color of the reddisplay was x=0.41, y=0.30, the color of the green display was x=0.31,y=0.36, and the color of the blue display was x=0.26, y=0.28. This isabout 70 percent the brightness of the conventional reflective typemonochrome liquid crystal device, and an equivalent contrast ratio.Because the red color is particularly highlighted, the colorreproducibility is insufficient. Consequently, it is more suitable forthe display of portable information machinery rather than the display ofvideo images.

Preferred Embodiment 10

FIG. 10 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device according to aspects ofthe present invention. The configuration is explained. 1001 is the upperpolarizing plate, 1002 is the element substrate, 1003 is the liquidcrystals, 1004 is the opposing substrate, 1005 is the lower polarizingplate, and 1006 is the scattering reflective plate. On the opposingplate 1004 are provided the opposing electrodes (scanning wires) 1011and the color filters 1010, and on the element substrate 1002 areprovided the signal wires 1007, the MIM elements 1008, and the pixelelectrodes 1009. The color filters 1010 are the dye scattering type, andthey consist of the three colors, red (“R” in the drawing), green (“G”in the drawing), and blue (“B” in the drawing).

FIG. 13 is a drawing showing the spectral properties of the colorfilters 1010. The horizontal axis of FIG. 13 is the light wavelength,the vertical axis is the transmissivity, 1301 and 1311 show the spectrumof the red filter, 1302 and 1312 show the spectrum of the green filter,and 1303 and 1313 show the spectrum of the blue filter. Also, 1301 and1311, 1302 and 1312, and 1303 and 1313 variously have the same colorfilter material, but their thicknesses are different, the former of eachbeing 0.8 μm and the latter being 0.2 cm. The average transmissivity ofthe red filters for the light in the 450 nm to 660 nm wavelength rangewas 28% when the thickness was 0.8 μm and 74% when the thickness was 0.2μm. Also, the average transmissivity of the green filters was 33% whenthe thickness was 0.8 cm and 75% when the thickness was 0.2 cm. Also,the average transmissivity of the blue filters was 30% when thethickness was 0.8 cm and 74% when the thickness was 0.2 cm.

FIG. 14 is a drawing having plotted the average transmissivity whenhaving variously changed the thickness of the color filters. In thedrawing, 1401 is the case of the blue filter, 1402 is the case of thegreen filter, and 1403 is the case of the red filter. All of the colorfilters have a trend whereby the average transmissivity becomes higheras the filter becomes thinner. The thickness of an ordinary dyescattering type color filter used in transmissive types is about 0.8 μm,but when having used such a color filter, it could only display so darkthat it couldn't be discriminated unless is under direct sunlightoutdoors or unless special illumination was performed with such as aspotlight. When the thickness was 0.23 μm or less, that is, when theaverage transmissivity of all the color filters was 70% or more, abrightness was obtained being comfortable to use in a comparativelybright room of about 1000 lux brightness, for example, in an environmentsuch as an office desk illuminated by a fluorescent lamp stand. When thethickness was 0.18 cm or less, that is, when each of the averagetransmissivity of all the color filters was 75% or more, a brightnesswas obtained being sufficient for use even under the ordinary roomillumination of about 200 lux. Also, when the thickness was 0.08 μm orless, that is the average transmissivity of all the color filters was90% or more, a display was possible such that the colors could berecognized clearly. Thus, for dye scattering type color filters, it isdesirable that their thickness be 0.23 cm or less, more preferably 0.1μm or less, and further preferably 0.08 μm or less.

Preferred Embodiment 11

FIG. 15 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device according to aspects ofthe present invention. First the configuration is explained. 1501 is theupper polarizing plate, 1502 is the element substrate, 1503 is theliquid crystals, 1504 is the opposing substrate, 1505 is the lowerpolarizing plate, and 1506 is the scattering reflective plate. On theopposing plate 1504 are provided the opposing electrodes (scanningwires) 1511 and the color filters 1510, and on the element substrate1502 are provided the signal wires 1507, the MIM elements 1508, and thepixel electrodes 1509. The light-variable area in one dot is an area inwhich a bump-shaped ITO on the element substrate overlaps with abar-shaped ITO on the opposing substrate, and that outline is shown witha broken line on the ITO of the opposing substrate. (Although a part isoverlaid by the color filters, please refer to FIG. 20, which shows thesame outline.)

The opposing electrodes 1511 and the pixel electrodes 1509 are formed oftransparent ITO, and the signal lines 1507 are formed of metallic Ta.The MIM elements are of a structure having sandwiched an insulating filmTa205 with metallic Ta and metallic Cr. The liquid crystals 1503 arenematic liquid crystals twisted 90°, and the Δn and cell gap d of theliquid crystal cells was selected such that the Δnxd of the liquidcrystal cells becomes 1.34 μm. Also, the upper and lower polarizingplates were arranged such that their absorption axes become parallelwith the rubbing axis of the adjacent substrate. This is theconfiguration of the TN mode being the brightest and having the leastcoloration. Also, the color filters 1510 are composed of the two colors,red (“R” in the drawing) and cyan (“C” in the drawing), being in amutually complementary relationship, but they are provided only on apart of the light-variable area.

FIG. 16 is a drawing showing the spectral properties of the colorfilters 1510. The horizontal axis of FIG. 16 is the light wavelength,the vertical axis is the transmissivity, 1601 shows the spectrum of thered filter, and 1602 shows the spectrum of the cyan filter. The averagetransmissivity, having simply averaged the transmissivities in the 450nm to 660 nm wavelength range, was 30% for the red filter, and 58% forthe cyan filter. However, this is when the color filters are provided onthe entire face, but when they are provided only on a part, the averagevalue in the light-variable area shall be called the averagetransmissivity.

FIG. 17 is the results having sought the average transmissivity byvariously changing the percentages of the areas providing the colorfilters within the light-variable area. 1701 is the averagetransmissivity in dots providing the red filter, and 1702 is the averagetransmissivity in the dots providing the cyan filter.

When the surface area ratio of the color filters was 100%, that is, whenthe color filters were provided on the entire face, the displays weredark such that they could not be discriminated unless under directsunlight outdoors or unless special illumination was performed with suchas a spotlight. When the surface area ratio of the color filters was 45%or less, that is, when the average transmissivity of all the colorfilters was 70% or more, a brightness was obtained being comfortable touse in a comparatively bright room of about 1000 lux brightness, forexample, in an environment such as an office desk illuminated by afluorescent lamp stand. When the surface area ratio of the color filterswas 35% or less, that is, when the average transmissivity of all thecolor filters was 75% or more, a brightness was obtained beingsufficient for use even under the ordinary room illumination of about200 lux. Also, when the surface area-ratio of the color filters was 15%or more, that is, when the average transmissivity of all the colorfilters was 90% or less, a display was possible such that the red andthe cyan could be discriminated. When the surface area ratio of thecolor filters was 25% or more, that is, when the average transmissivitywas also 90% or less, a display was possible such that the colors couldbe recognized clearly. Also, when all the color filters were provided, ahigh contrast ratio of 1:15 could be obtained.

The color filters used in Preferred Embodiment 11, excluding the pointsusing the cyan color, are ordinary color filters used in transmissivetypes, and they are of the same extent of spectral properties and thesame extent of brightness. For such color filters, it is desirable thatthey be provided on 45% or less of the light-variable area, preferably35% or less, moreover, that they be provided on 15% or more, preferably25% or more of the area.

In Preferred Embodiment 1, MIM elements were used as the activeelements, but this was because they are rather useful in increasing theaperture, but if the aperture is the same, there is no change in theeffect of the present invention even when using TFT elements.

Preferred Embodiment 12

Preferred Embodiment 12 also is a reflective type color liquid crystaldevice according to aspects of the present invention. Its structure isthe same as the reflective type color liquid-crystal device of PreferredEmbodiment 11 shown in FIG. 15, but the properties of the color filtersare different.

FIG. 18 is a drawing showing the spectral properties of the colorfilters used in Preferred Embodiment 2. The horizontal axis of FIG. 18is the light wavelength, the vertical axis is the transmissivity, 1801shows the spectrum of the red filter, and 1802 shows the spectrum of thecyan filter. The average transmissivity was 41% for the red filter, and62% for the cyan filter. As color filters that can be fabricatedaccording to conventional processes without the problems of dyedistribution, and the like, this extent of brightness is the maximum.

FIG. 19 is the results having sought the average transmissivity byvariously changing the percentages of the areas providing the colorfilters within the light-variable area. 1901 is the averagetransmissivity in dots providing the red filter, and 1902 is the averagetransmissivity in the dots providing the cyan filter.

When the surface area ratio of the color filters was 100%, that is, whenthe color filters were provided on the entire face, the displays weredark such that they could not be discriminated unless under directsunlight outdoors or unless special illumination was performed with suchas a spotlight. When the surface area ratio of the color filters was 50%or less, that is, when the average transmissivity of all the colorfilters was 70% or more, a brightness was obtained being comfortable touse in a comparatively bright room of about 1000 lux brightness, forexample, in an environment such as an office desk illuminated by afluorescent lamp stand. When the surface area ratio of the color filterswas 40% or less, that is, when the average transmissivity of all thecolor filters was 75% or more, a brightness was obtained beingsufficient for use even under the ordinary room illumination of about200 lux. Also, when the surface area ratio of the color filters was 15%or more, that is, when the average transmissivity of all the colorfilters was 90% or less, a display was possible such that the red andthe cyan could be discriminated. When the surface area ratio of thecolor filters was 25% or more, that is, when the average transmissivitywas also 90% or less, a display was possible such that the colors couldbe recognized clearly. Also, when all the color filters were provided, ahigh contrast ratio of 1:15 could be obtained.

The color filters used in Preferred Embodiment 12 were completely clearwhen compared with the color filters used in the ordinary transmissivetypes. For such color filters, it is desirable that they be provided on50% or less of the light-variable area, preferably 40% or less,moreover, that they be provided on 15% or more, preferably 25% or moreof the area.

Preferred Embodiment 13

FIG. 20 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device according to aspects ofthe present invention. The configuration is explained. 2001 is the upperpolarizing plate, 2002 is the element substrate, 2003 is the liquidcrystals, 2004 is the opposing substrate, 2005 is the lower polarizingplate, and 2006 is the scattering reflective plate. On the opposingplate 2004 are provided the opposing electrodes (scanning wires) 2011and the color filters 2010, and on the element substrate 2002 areprovided the signal wires 2007, the MIM elements 2008, and the pixelelectrodes 2009. Also, the light-variable area in one dot is an area inwhich a bump-shaped ITO on the element substrate overlaps with abar-shaped ITO on the opposing substrate, and that outline is shown witha broken line on the ITO of the opposing substrate.

The color filters 1510 are composed of the two colors, red (“R” in thedrawing) and cyan (“C” in the drawing), being in a mutuallycomplementary relationship, and they are provided substantially in themiddle of the light-variable area. It is desirable that it be arrangedsuch that there are no other color filters in the perimeter of thevarious color filters. By being arranged in this manner, a displayhaving little color blending is possible. The reason why is that,ordinarily, because there exists a distance of only the thickness of atleast the opposing substrate between the color filter layer and thereflective plate, color mixing occurs by the light introduced throughthe red filter and being emitted through the cyan filter or the reverse,but in the arrangement mentioned above, such a probability is reduced.

Preferred Embodiment 14

FIG. 21 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device according to aspects ofthe present invention. The configuration is explained. 2101 is the upperpolarizing plate, 2102 is the element substrate, 2103 is the liquidcrystals, 2104 is the opposing substrate, 2105 is the lower polarizingplate, and 2106 is the scattering reflective plate. On the opposingplate 2104 are provided the opposing electrodes (scanning wires) 2112and the color filters 2111, and on the element substrate 2102 areprovided the signal wires 2107, the MIM elements 2108, and the pixelelectrodes 2109.

The color filters 2111 are composed of the two colors, red (“R” in thedrawing) and cyan (“C” in the drawing), being in a mutuallycomplementary relationship, and they are arranged variously divided infive areas in the middle of the light-variable area forming a checkeredshape. If the color filters are provided only on a part of the dots, theparts not having the color filters are white and easy to see, but ifthey are divided into fine areas in this manner, it has the advantagethat the color mixing is good. The number of divisions of course may betwo, but the effect is greater when being divided into three or more.

Also, black masks (“BK” in the drawing) are provided in the positionscovering the scanning wires. These black masks particularly have theeffect of preventing reflection when the opposing substrate 2104 in FIG.21 is positioned on the upper side and the element substrate 2102 ispositioned on the lower side. Also, even if the black dye is not useddeliberately, it may be substituted by the red, cyan or theircombination.

Preferred Embodiment 15

Preferred Embodiment 15 is a reflective type color liquid crystal deviceaccording to aspects of the present invention. However, its structure isidentical to the reflective type color liquid crystal device ofPreferred Embodiment 12 shown in FIG. 15, the reflective type colorliquid crystal device of Preferred Embodiment 13 shown in FIG. 20, andthe reflective type color liquid crystal device of Preferred Embodiment14 shown in FIG. 21.

Its characteristics is in the point that the color filters are providedin the positions between the electrodes and the liquid crystals.Generally, color filters are provided in the positions between theelectrodes and the substrate in order to print the voltage effectivelyon the liquid crystals. However, by arranging them in the manner of thepresent preferred embodiment, two new effects are obtained. One is theexpansion of the visual angle, and another is the improvement of thecolor purity in the intermediate tones.

FIG. 22 is a drawing showing the voltage reflectivity properties of thereflective type color liquid crystal device in Preferred Embodiment 15of the present invention. The horizontal axis is the voltage effectivelyprinted on the liquid crystals, and the vertical axis is the referencereflectivity set to 100% when the voltage is not printed. 2201 is theproperties of the areas not having color filters within thelight-variable areas, and 2202 is the properties of the areas having thecolor filters. Because of the voltage effect due to the division ofcapacity, the sharpness of 2202 is worse in the voltage reflectivityproperties than 2201. In other words, it is harder for the voltage to beprinted on the liquid crystals when the areas having the color filtersare compared with the areas not having them. Because two areas existwithin a single pixel, having different voltage-spending conditions inthis manner, the visual angle properties are improved by the effect(generally called the “halftone effect”) disclosed in the publication ofJapanese Laid-Open Patent No. 2-12 and the publication of JapaneseLaid-Open Patent No. 4-348323. Also, because the areas having the colorfilters always have a higher reflectivity in the intermediate tonedisplay state, there is also the effect of the colors being displayedricher.

Preferred Embodiment 16

FIG. 23 is a drawing showing the structure of the color filter substrateof a reflective type color liquid crystal device according to aspects ofthe present invention, (a) is a frontal view, and (b) is a crosssection. First, the configuration is explained. The rectangular area2304 surrounded by the broken line of (a) shows one dot. 2309 is theglass substrate, 2301 is the red filter, 2303 is the green filter, 2302is the blue filter, 2305 is the gap between dots, the hatched area 2308is acryl, 2307 is a protective film, and 2306 is a transparent ITOelectrode.

The spectral properties of the color filters used here are shown in FIG.25. The horizontal axis of FIG. 25 is the light wavelength, the verticalaxis is the transmissivity, 2501 shows the spectrum of the blue filter,2502 shows the spectrum of the green filter, and 2503 shows the spectrumof the red filter. However, these are the properties when the areaformed by the color filters is 100%. A color filter showing suchspectral properties is formed on 50% of the proportion of the areawithin one dot 2304 of FIG. 23. Thus, the spectral properties shown inFIG. 26 were obtained, being the average within one dot. The horizontalaxis of FIG. 26 is the light wavelength, the vertical axis is thetransmissivity, 2601 shows the spectrum of the blue filter, 2602 showsthe spectrum of the green filter, and 2603 shows the spectrum of the redfilter.

Furthermore, the portions not formed by the color filters of FIG. 23have formed acryl 2308 at the same thickness as the color filters. Thethickness of the color filters 2301, 2302, 2303, and the acryl 2308 atthis time is about 0.2 μm for each. Also, without forming alight-blocking film (black stripe) as usually formed by transmissivetype color liquid crystal devices in the space between the dots, atransparent acryl layer 2308 was formed also in the gap 2305 between thedots. Furthermore, a liquid crystal device was composed by formingsequentially on these a protective film 2307, an ITO electrode 2306, andan orientation film (not illustrated) for orienting the liquid crystals,and combining them with a MIM (metal-insulator-metal) active matrixsubstrate. The TN mode was selected for the liquid crystal mode at thistime.

FIG. 24 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device in Preferred Embodiment16. 2402 is the element substrate, 2403 is the opposing substrate, 2406is the MIM element, 2407 is the display electrode of one dot, 2408 isthe scanning wire, 2401 is the upper polarizing plate, 2409 is thepartially formed red filter, 2410 is the partially formed green filter,2411 is the partially formed blue filter, 2413 is the signal electrode,2404 is the lower polarizing plate, and 2405 is an aluminum reflectiveplate.

A reflective type color liquid crystal device using a substrate haringformed color filters only on 50% of the proportion of the area withinone dot had the liquid crystal orientation become confused by thedifference of levels of the portions formed with color filters and theportions not formed with color filters, and the contrast was 1:8. Asopposed to this, a reflective type color liquid crystal device using asubstrate having formed acryl at the same thickness as the color filterson the portions not formed with color filters did not have theorientation of the liquid crystals become confused, and ahigh-image-quality display was possible. The contrast at this time was1:20. The color filter configuration when not forming a transparentacryl layer on the portions not formed with color filters is shown inFIG. 27. (a) is a frontal view, and (b) is a cross section. 2707 is theglass substrate, 2701 is the partially formed red filter, 2703 is thepartially formed green filter, 2702 is the partially formed blue filter,2706 is a protective film, 2704 is one dot, and 2705 is the gap betweenthe pixels. As is clear from the cross section of (b), there exists anirregularity on the surface of the color filters, and by such a surfacecondition is confused the liquid crystal orientation.

In the present preferred embodiment, the color filter substrate of thepresent invention was combined with a MIM substrate, but a TFT substrateand a TFD (thin film diode) also may be used. Also, in the presentpreferred embodiment was described about an active matrix reflectivetype color liquid crystal device, but the present invention also may beapplied to a simple matrix reflective type color liquid crystal device.When the surface irregularity of the substrate greatly influences theliquid crystal orientation as in the STN mode, the present invention isfurther effective. Also, in the present preferred embodiment, a “mosaicarrangement” was selected for the color filter arrangement, but“triangle arrangements” and “stripe arrangements” also may be used as inp. 321 of Latest Liquid Crystal Process Technology '93 (Puresu Janaruy).

Preferred Embodiment 17

FIG. 28 is a drawing showing the structure of the color filters of areflective type color liquid crystal device according to aspects of thepresent invention. (a) is a frontal view, and (b) is a cross section.First, the configuration is explained. The rectangular area 2804surrounded by the broken line of (a) shows one dot. 2808 is the glasssubstrate, 2807 is the ITO electrode, 2801 is the red color filter, 2803is the green color filter, 2802 is the blue color filter, and thehatched area 2806 is acryl.

The spectral properties of the color filters used here are shown in FIG.29. The horizontal axis of FIG. 29 is the light wavelength, the verticalaxis is the transmissivity, 2901 shows the spectrum of the blue filter,2902 shows the spectrum of the green filter, and 2903 shows the spectrumof the red filter. However, these are the properties when the areaformed by the color filters is 100%. A color filter showing suchspectral properties is formed on 30% of the proportion of the areawithin one dot of FIG. 28. Thus, the spectral properties shown in FIG.26 were obtained, being the average within one dot.

Furthermore, the portions not formed by the color filters of FIG. 28have formed acryl 2807 at the same thickness as the color filters. Thethickness of the color filters and the acryl at this time is about 0.8μm for each, and, without forming a light-blocking film (black stripe)as usually formed by transmissive type color liquid crystal devices inthe space between the dots, a transparent acryl layer 2807 was formedalso in the gap between the dots. Furthermore, a liquid crystal devicewas composed by forming an orientation film for orienting the liquidcrystals, and combining it with a TFT substrate. The TN mode wasselected for the liquid crystal mode at this time, polarizing plateswere affixed variously to the outsides of the glass substrate, and asilver reflective plate was further placed on the opposite side of theobserved side.

A reflective type color liquid crystal device using a substrate havingformed color filters only on 30% of the proportion of the area withinone dot had the liquid crystal orientation become confused by thedifference of levels of the portions formed with color filters and theportions not formed with color filters, and the contrast was 1:5. Asopposed to this, a reflective type color liquid crystal device using asubstrate having formed acryl at the same thickness as the color filterson the portions not formed with color filters did not have theorientation of the liquid crystals become confused, and ahigh-image-quality display was possible. The contrast at this time was1:18.

In the present preferred embodiment, the color filter substrate of thepresent invention was combined with a TFT substrate, but an MIMsubstrate and a TFD substrate also may be used. Also, in the presentpreferred embodiment was described about an active matrix reflectivetype color liquid crystal device, but the present invention also may beapplied to a simple matrix reflective type color liquid crystal device.When the surface irregularity of the substrate greatly influences theliquid crystal orientation as in the STN mode, the present invention isfurther effective.

In Preferred Embodiment 16 and Preferred Embodiment 17, the threecolors, RGB, were used for the color filters, but two colors of colorfilters being in a mutually complementary relationship may be used, suchas the cyan 3001 and red 3002 shown in FIG. 30, the magenta 3101 andgreen 3102 shown in FIG. 31, or yellow and blue.

Preferred Embodiment 18

In Preferred Embodiment 16 and Preferred Embodiment 17, the colorfilters were partially formed substantially in the middle of one dot,but they also may be formed in the positions as shown in FIGS. 32 (a)and (b). (a) shows the area 3202, being the upper or lower half of theone dot 3201 having formed color filters, and the area 3203, being theremaining half not having formed color filters. (b) shows the area 3202,being the right or left half of the one dot 3201 having formed colorfilters, and the area 3203, being the remaining half not having formedcolor filters. Also, as shown in FIGS. 32 (c) and (d), the one dot 3201also may be divided into two or more, and one part may be made as thearea 3202 having formed the color filters, and the remainder may be madeas the area 3203 not having formed color filters. Even using colorfilters in the various patterns as such, high-image-quality reflectivetype color liquid crystal devices still could be realized.

Preferred Embodiment 19

Table 1 shows the change in properties when having changed thedifference of levels of the reflective layer and the color filters inPreferred Embodiment. As the difference of levels becomes smaller, theimage quality/contrast go up together. If the difference in levels is0.5 μm, a contrast of 1:10 or more can be obtained, and if it furtherbecomes 0.1 μm, a contrast of 1:15 can be obtained.

Preferred Embodiment 20

In Preferred Embodiment 16 and Preferred Embodiment 17, acryl was usedin the transparent layer filling the difference in levels between theparts formed and not formed with color filters, but high-image-qualityreflective type color liquid crystal devices could be realized also byusing polyimide. Also, high-image-quality reflective type color liquidcrystal devices could be realized also by using polyvinyl alcohol in thetransparent layer in the same manner. These results are shown in Table2. Compared with the case not having a transparent layer, both the imagequality and the contrast are improved.

In Preferred Embodiment 16 and Preferred Embodiment 17, aluminumreflective plates and silver reflective plates were used, being commonfor reflective plates, but the holographic reflective plates publishedby A. G. Chen, et al. (SID '95 Digest, pp. 176-179) also may be used.

Preferred Embodiment 21

FIG. 33 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device according to aspects ofthe present invention. The configuration is explained. 3301 is the upperpolarizing plate, 3302 is the element substrate, 3303 is the liquidcrystals, 3304 is the opposing substrate, 3305 is the lower polarizingplate, and 3306 is the scattering reflective plate. On the opposingsubstrate 3304 are provided the opposing electrodes (scanning wires)3311 and the color filters 3310, and on the element substrate 3302 areprovided the signal wires 3307, the MIM elements 3308, and the pixelelectrodes 3309.

The color filters 3310 are composed of the two colors, red (“R” in thedrawing) and cyan (“C” in the drawing), being in a mutuallycomplementary relationship, but on part of the dots there are notprovided color filters. The color filters used here are the same asPreferred Embodiment 1, and their spectral properties are shown in FIG.16.

FIG. 34 is a drawing showing the orientation of the color filters in theform viewing FIG. 33 from above. “R” in the drawing shows a dot having ared filter, “C” shows a dot having a cyan filter, and “W” shows a dothaving no color filter. On ⅓ of the entirety of dots was provided redfilters, on ⅓ of the dots was provided cyan filters, and on theremaining ⅓ of the dots was provided no filters. Also, FIGS. 34 (a),(b), (c), and (d) show the distribution of the on dots and off dots whenhaving displayed variously white, red, cyan, and black. The dots havinghatching applied are the on dots, that is, the dark state, and the dotsnot having the hatching applied are the off dots, that is, the brightstate. When performing display in this manner, because the color displayis performed with ⅔ of the entirety of the dots, a display brighter thanusual becomes possible. Also, even when displaying intermediate toneswith a color display, if the brightness is adjusted mainly by the dotsnot having color filters, it has the merit of always being able todisplay brilliant colors. For example, when displaying dark red, half ofthe dots having color filters can be turned on with all the dots havingred filters turned off and the dots having cyan filters turned on.

Another color filter placement is shown in FIG. 35. On ¼ of the entiretyof the dots were placed the red filters, on ¼ of the dots were placedthe cyan filters, and on the remaining ½ of the dots were not placedcolor filters. Also, FIGS. 35 (a), (b), (c), and (d) show thedistribution of the on dots and off dots when displaying variouslywhite, red, cyan, and black. When performing such displays, because thecolor display is performed with ¾ of the entirety of the dots, a displayeven brighter than the color filter placement of FIG. 35 is possible.

As another example, the placement when using three colors of filters,red, green, and blue, is shown in FIG. 36. The “R” in the drawing showsthe dots having red filters, “G” shows the dots having green filters,“B” shows the dots having blue filters, and “W” shows the dots nothaving color filters. On ⅙ of the entirety of the dots were provided thered filters, on ⅙ of the dots were provided the green filters, on ⅙ ofthe dots were provided the blue filters, and on the remaining ½ of thedots were not provided color filters. Also, FIGS. 36 (a), (b), (c), and(d) show the distribution of the on dots and off dots when displayingvariously white, red, green, and blue. When performing such displays,because the color display is performed with 4/6 of the entirety of thedots, a bright display is possible.

Also, a configuration is possible in which the red filters are providedon ⅙ of the entirety of the dots, the green filters are provided on ⅙ ofthe dots, the blue filters are provided on ⅙ of the dots, and no filtersare provided on ½ of the dots. When performing such displays, becausethe color display is performed with ½ of the entirety of the dots, abright display is possible.

Preferred Embodiment 22

FIG. 37 is a drawing showing an outline of the structure of a reflectivetype color liquid crystal device according to aspects of the presentinvention. The configuration is explained. 3701 is a frame case, 3702 isthe upper polarizing plate, 3703 is the upper substrate, the hatchedarea of 3704 is the color filters, 3705 is the lower substrate, and 3706is the polarizing plate with the reflecting plate attached. Because thefigure is complicated, the transparent electrodes, nonlinear elements,signal wires, orientation film, and the like, have been omitted. Also,3711 is the drive display area, 3712 is the effective display area, and3713 is the area having the color filters. (b) is a horizontal crosssection, but the vertical cross section is identical to (b). The terms“drive display area” and “effective display area” are defined in theElectronic Industry Association of Japan (EIAJ) standard ED-2511A as“the area possessing the display function in a liquid crystal displaydevice” and “the effective area as the drive display area and thescreens following that,” respectively. That is, the drive display areais the area capable of expending voltage in the liquid crystals, and theeffective display area is all the area of the liquid crystal panel nothidden by the frame case.

The properties of Preferred Embodiment 22 have the area 3713 having thecolor filters the same or wider than the effective display area 3712. Bybeing configured in this manner, the reflective type color liquidcrystal device of Preferred Embodiment 22 has the advantage of thedisplay being brightly visible. Ordinarily, with a transmissive typecolor liquid crystal device, the color filters are provided only on thedrive display areas, and on the area outside that is provided a blackmask made of metal or resin. As a matter of fact, in reflective typecolor liquid crystal devices, metallic black masks cannot be usedbecause they add glare. Also, because resinous black masks originallyare not provided for color filters, it becomes an increase in cost. Thereason is that, if nothing is provided outside the drive display area,the outside becomes dark, and the drive display area appears relativelydark. Thus, the provision of the same color filters inside as well asoutside the drive display areas, preferably in the same pattern, iseffective in showing a brighter display.

Preferred Embodiment 23

In a transmissive type color liquid crystal device, generally a blackmask is provided outside the dots, but if a black mask is provided in areflective type color liquid crystal device, while a high contrast isobtainable, on the contrary, the display becomes extremely dark.Particularly in liquid crystal modes in which the parallax isunavoidable, such as the TN mode and the STN mode, because the light isabsorbed two times by the black mask when introduced and when emitted,the brightness has a quality substantially proportional to the square ofthe aperture. Consequently, a black mask cannot be provided in areflective type color liquid crystal device, but conversely, if nolight-absorbing body is provided whatsoever outside the dots, thecontrast decreases markedly, being undesirable. Thus, this aspect of thepresent invention does not provide a black mask outside the dots, ratherit comprises color filters having the same extent or less absorption asthe areas inside the dots.

FIG. 38 is a drawing showing the placement of the color filters of areflective type color liquid crystal device according to aspects of thepresent invention. The fundamental configuration and spectral propertiesof the color filters are identical to FIG. 6 of Preferred Embodiment 5,but pains were taken in the placement of the color filters in the areaoutside the dots. In FIG. 38, the “horizontally protruding” area shownin 3801 is the area in which the opposing electrodes and the pixelelectrodes are overlaid and the electric field is imprinted in theliquid crystals. Also, the area 3802 having applied hatching slantedfrom the top right to the bottom left is the cyan filters, and the area3803 having applied cross hatching is the red filters.

In FIG. 38(a), the red filters and cyan filters are placed so as to beclosely touching outside the dots. Also, in (b), filters are providedoutside the dots as well, but they are placed apart from each other.Also, in (c), red filters are placed outside the dots. Because there isa non-zero absorption in the area outside the dots that is the sameextent or less than that inside the dots, a bright, high-contrastdisplay is obtainable. For the various properties, (a) had areflectivity of 30% and a contrast ratio of 1:15 during white display,(b) had a reflectivity of 33% and a contrast ratio of 1:13, and (c) had29% and 1:16.

Preferred Embodiment 24

FIG. 39 is a drawing showing the placement of the color filters of areflective type color liquid crystal device according to aspects of thepresent invention. The fundamental configuration and spectral propertiesof the color filters are identical to FIG. 8 of Preferred Embodiment 9and FIG. 12, but pains were taken in the placement of the color filtersoutside the dots. In FIG. 39, the “horizontally protruding” area shownin 3901 is the area in which the opposing electrodes and the pixelelectrodes are overlaid and the electric field is imprinted in theliquid crystals. Also, the area 3902 having applied hatching slantedfrom the top left to the bottom right is the blue filters, the area 3903having applied hatching slanted from the top right to the bottom left isthe green filters, and the area 3904 having applied cross hatching isthe red filters.

In FIG. 39(a), the three colors of filters are placed outside the dotsas well, but they are placed apart from each other. The distance apartwas set anticipating the maximum alignment error during fabrication ofthe color filters. That is, FIG. 39(b) is the color filter placementwhen having anticipated the expected maximum alignment error, but evenin this case the color filters of different colors are made such thatthey do not overlap each other. Because the overlapping of the colorfilters has substantially the same significance as the existence of ablack mask, this must be avoided to the extent possible. By placing thecolor filters in the above manner, a bright, high-contrast reflectivetype color liquid crystal device was possible.

Preferred Embodiment 25

FIG. 40 is a drawing showing the essential elements of a reflective typecolor liquid crystal device according to aspects of the presentinvention. First the configuration is explained. 4001 is the upperpolarizing plate, 4002 is the opposing substrate, 4003 is the liquidcrystals, 4004 is the element substrate, 4005 is the lower polarizingplate, and 4006 is the scattering reflecting plate. On the opposingsubstrate 4002 are provided the color filters 4007 and the opposingelectrodes (scanning wires) 4008, and on the element substrate 4004 areprovided the signal wires 4009, the pixel electrodes 4010, and the MIMelements. These color filters are in the stripe arrangement common withthe data displays of PCs and the like. The spectral properties of thecolor filters are identical to FIG. 12 of Preferred Embodiment 9.

FIG. 41 is a drawing showing the placement of the color filters of areflective type color liquid crystal device according to aspects of thepresent invention. In FIG. 41, the “horizontally protruding” area shownin 4101 is an area in which the opposing electrodes and the pixelelectrodes are overlaid and the electric field is imprinted in theliquid crystals. Also, the area 4102 having applied hatching slantedfrom the top left to the bottom right is the blue filters, the area 4103having applied hatching slanted from the top right to the bottom left isthe green filters, and the area 4104 having applied cross hatching isthe red filters.

In FIG. 41(a), the three colors of filters are placed outside the dotsas well, but they are placed continuously up and down, and they areplaced apart from each other left and right. The distance apart was setanticipating the maximum alignment error during fabrication of the colorfilters. That is, FIG. 41(b) is the color filter placement when havinganticipated the expected maximum alignment error, but even in this casethe color filters of different colors are made such that they do notoverlap each other. By placing the color filters in the above manner, abright, high-contrast reflective type color liquid crystal device waspossible.

Preferred Embodiment 26

FIG. 42 is a drawing showing the essential elements of the structure ofa reflective type color liquid crystal device according to aspects ofthe present invention. The configuration is explained. 4201 is the upperpolarizing plate, 4202 is the element substrate, 4203 is the liquidcrystals, 4204 is the opposing substrate, 4205 is the lower polarizingplate, and 4206 is the scattering reflective plate. On the elementsubstrate 4202 are provided the signal wires 4207 and the pixelelectrodes 4208, and on the opposing substrate are provided the opposingelectrodes (scanning wires) 4209. They do not appear on this crosssection, but the signal wires and the pixel electrodes are connected viaMIM elements. Also, on the surface of the reflective plate side of theopposing substrate are provided the red filters 4210, the green filters4211, and the blue filters 4212.

The spectral properties of the color filters are given the properties asshown in FIG. 12 if provided on the entirety of the dots, or as shown inFIG. 16 and FIG. 18 according to the proportion if provided on a part ofthe dots.

By providing the color filters on the outside of the substrate in thismanner, the use of cheap color filters is possible. These color filtersalso may be provided on top of a film, or the like, and affixed later.Also, particularly by providing the color filters only on a part of thedots, it has the advantages of the assembly margin being expanded, andthe visual field being widened.

Preferred Embodiment 27

Preferred Embodiment 27 is a reflective type color liquid crystal deviceaccording to aspects of the present invention. Its structure isidentical to FIG. 1 of Preferred Embodiment 1, FIG. 6 of PreferredEmbodiment 6, and FIG. 8 of Preferred Embodiment 7. Its characteristicsare in the fact that on the substrate 104, 604, 804 positioned on theside of the reflective plate are provided the MIM elements 111, 611,811. By being positioned in this manner, compared with the case of thereverse configuration, that is, having provided the MIM elements on thesubstrate 102, 602, 802, unwanted surface reflection is reduced, and ahigh contrast was obtained. There are three reasons for this. One isthat the reflections by the signal wires 109, 609, 809 and the MIMelements are partially absorbed by the color filters 107, 607, 807. Thesecond is that the signal wires themselves are of a structure havingsuperimposed metallic Ta and metallic Cr. The third is that thereflected light incurs absorption due to the interference of multiplerefraction by passing through the liquid crystal layer 103, 603, 803.

Preferred Embodiment 28

Preferred Embodiment 28 is a reflective type color liquid crystal deviceaccording to aspects of the present invention. Its overall structure isidentical to, for example, FIG. 8 of Preferred Embodiment 7. Itcharacteristics are in the wiring method of the MIM elements.

FIG. 43 is a drawing showing the wiring method of the MIM elements ofthe reflective type color liquid crystal device in Preferred Embodiment28. 4101 is the signal wires, 4302 is the MIM element, and 4303 is thepixel electrodes. Because the pixel electrodes variously face the red,green, and blue color filters of the opposing substrate, thecorresponding relationships are shown by “R,” “G,” and “B” on the pixelelectrodes.

Each dot of FIG. 43 is in a vertically long shape, and one square pixelis formed by three dots arrayed horizontally. This is a configurationoften seen with the data displays of PCs. Here, the signal wires arewired parallel to the short edges of the dots, that is, in thehorizontal direction. By being wired in this manner, it has the effectsof the number of wires becoming less, and the aperture becoming higher.Here, aperture is the percentage of the area occupied excluding thenon-transparent portion of the metal, and the like.

This is compared with the conventional configuration. FIG. 44 is adrawing showing the wiring method of a (transmissive) color liquidcrystal device using conventional MIM elements. 4401 is the signalwires, 4402 is the MIM element, and 4403 is the pixel electrodes. Thedot pitch is the same as FIG. 43, and the dots are formed verticallylong, but the signal wires are wired parallel to the long edges of thedots, that is, in the vertical direction. When wired in this manner, thenumber of wires becomes three times the case of FIG. 43, and theaperture is low. One of the reasons such wiring was performed in thepast was because vertical wiring on a horizontal panel has a shorterdistance, and another was because if a black mask is provided, theaperture does not change whether vertically wired or horizontally wired.

When the aperture becomes higher in this manner, the display becomesbrighter. That the aperture is beneficial to brightness, and that it isparticularly evident in a reflective configuration having parallax,already have been explained in detail from Preferred Embodiment 23 to25.

Preferred Embodiment 29

FIG. 45 shows the properties of a reflective type color liquid crystaldevice according to aspects of the present invention. Taking the sameconfiguration as Preferred Embodiment 2, the relationships between thedrive surface area ratio and contrast, and the drive surface area ratioand reflectivity when having changed the drive surface area ratio from50% to 100% are shown. Here, drive surface area ratio is defined as thepercentage occupied by the area driven by the liquid crystals within theareas excluding the non-transparent portions of the pixels, such as themetallic wiring, the MIM elements, and the like. The horizontal axistakes the drive surface area ratio, the vertical axis takes the contrastand reflectivity, 4501 is the contrast of the present preferredembodiment, 4502 is the contrast of a comparative example, 4503 is thereflectivity during cyan display of the present preferred embodiment,and 4504 is the reflectivity during cyan display of the comparativeexample.

If the drive surface area ratio is 60% or more, a good contrast of 1:5or more can be obtained. Also, if the drive surface area ratio is 85% orless, a good brightness of 23% or more in cyan display can be obtained.

Preferred Embodiment 30

In a reflective type color liquid crystal display device, the propertiesof the scattering reflective plate greatly control the properties ofbrightness, contrast, and visual angle. There are various types ofscattering reflective plates, from those having weak scatteringproperties, such as mirror faces, to those having strong scatteringproperties, such as paper, and they are selected according to theperipheral environment, but for a reflective type color liquid crystaldisplay device, one with weak scattering properties is desirable, asbrightness and contrast are deemed important.

FIG. 46 and FIG. 47 are drawings showing the properties of thereflective plates of reflective type color liquid crystal devicesaccording to aspects of the present invention. In FIG. 46, 4604 is thescattering reflective plate, 4601 is the light introduced at a 45° angleonto the surface of the scattering reflective plate, 4602 is the lightof the positive reflection, and 4603 is a 30° cone centering thepositive reflection. Also, the horizontal axis of FIG. 47 is thelight-receiving angle of the reflected light, and the vertical axis isthe relative reflective strength. The reflective plate of PreferredEmbodiment 30 has the property that about 95% introduced light isreflected into the 30° cone. If this does not meet 80%, a contrast ratioof 1:10 cannot be obtained in an ordinary room environment.

For the purpose of reference, in FIG. 48 are shown the results of acomputer simulation. The horizontal axis of the drawing is thepercentage of the light reflected into the 30° cone shown in FIG. 46,and the vertical axis of the drawing is the brightness and contrastratio. The light source is hypothesized as completely scattered whitelight such as an integrating sphere, and the light reflected in thenormal line direction of the substrate is computed. The brightness isset as 100% the brightness of a standard white plate. As is clear fromthese simulation results, display can be obtained being as bright and ashigh-contrast as the percentage of the light reflected into the 30° coneis high, that is, as the scattering of the reflective plate is weak.However, it was confirmed that, with a reflective plate such that lightmore than 95% of the introduced light is reflected into the 30° cone,the visual angle properties are markedly narrow, and it cannot stand topractical use.

Preferred Embodiment 31

FIG. 49 is a drawing showing the essential components of the structureof a reflective type color liquid crystal device according to aspects ofthe present invention. First the configuration is explained. 4901 is theupper polarizing plate, 4902 is the opposing plate, 4903 is the liquidcrystals, 4904 is the element substrate, 4905 is the lower polarizingplate, 4906 is a semi-transmissive reflective plate, and 4912 isbacklights. On the opposing plate 4902 are provided the color filters4907 and the opposing electrodes (scanning wires) 4908, and on theelement substrate 4904 are provided the signal wires 4909, the pixelelectrodes 4910, and the MIM elements 4911. Also, the color filter hasthe identical spectral properties as FIG. 3 of Preferred Embodiment 2.

Since the reflectivity of a semi-transmissive plate is about 70 percentthat of an ordinary, scattering reflective plate, when used in areflective mode without lighting backlights, the reflectivity duringwhite color display becomes about 24%. Meanwhile, in a transmissive modehaving lit the backlights, a sufficient brightness can be obtained evenwith monochrome backlights having a surface brilliance of 400 cd/m².Also, the properties of the color filters such as shown in FIG. 3 are ofa transmissive nature and are not sufficient for display of colors, butwhen using a semi-transmissive plate, there is the effect of raising thecolor purity with the reflection of the ambient light even in atransmissive mode.

For a semi-transmissive plate, one that reflects 80% or more of theintroduced light is desirable for obtaining a bright display. Thedisplay necessarily becomes dark when used in a transmissive mode, butthe pursuit of the brightness of a transmissive mode, once obtained,easily becomes unsatisfactory as a result for both a transmissivedisplay and a reflective display. It is clear that a transmissive modeshould be totally dark and should barely visible for a display to beobtained that is easily sold on the market.

Preferred Embodiment 32

Preferred Embodiment 32 relates to a reflective type color liquidcrystal device according to aspects of the present invention, but thefundamental configuration and spectral properties of the color filtersare identical to FIG. 6 of Preferred Embodiment 5 and FIG. 3. Itscharacteristic is in that the cell conditions of the TN mode areoptimized in the reflective type color liquid crystal device.

FIG. 50 is a drawing showing the relationships of each axis of thereflective type liquid crystal device in Preferred Embodiment 32. 5021is the left and right direction (lengthwise direction) of the liquidcrystal panel, 5001 is the direction of the transmissive axis of theupper polarizing plate, 5002 is the rubbing direction of the polarizingplate placed above, 5003 is the rubbing direction of the elementsubstrate placed below, and 5004 is the direction of the transmissiveaxis of the lower polarizing plate. Here, the angle 5011 formed by therubbing direction of the opposing substrate and the left and rightdirection of the liquid crystal panel is set to 45°, the angle 5012formed by the direction of the transmissive axis of the upper polarizingplate and the rubbing direction of the opposing plate is set to 90°, theangle 5013 of the twist of the liquid crystals is set to right 90°, andthe angle 5014 formed by the direction of the transmissive axis of thelower polarizing plate and the rubbing direction of the elementsubstrate is set to 90°. If placed in such a manner, when the moleculesof the center of the liquid crystal layer are voltage printed, theystand up from the side of the viewer (that is, the lower side of thedrawing), and in conjunction with the visual angle properties of the TNliquid crystals, a high-contrast display not tending toward reflectionsbecomes possible. Also, the placement whereby the transmissive axis ofthe polarizing plates are perpendicular to the rubbing directions of theadjacent substrates (so-called O mode) has less color variation due torelative direction compared with the parallel placement (so-called Emode), and is more desirable.

Also, by making the multiple refractivity Δn of the liquid crystalmaterial 0.189 and the cell gap 7.1 μm, the Δnxd of a liquid crystalcell is set as 1.34 μm. This is the condition of most brightness andleast coloration during non-selective voltage printing. There areproblems that at Δnxd<1.30 μm the display color becomes bluish, and atΔnxd>1.40 μm the display becomes dark, and these are not desirable.

Preferred Embodiment 33

Preferred Embodiment 33 relates to a reflective type color liquidcrystal device according to aspects of the present invention. Itscharacteristics is in that the cell conditions of the TN mode arefurther optimized in the reflective type color liquid crystal device.

FIG. 50 is a drawing showing the relationships of each axis of thereflective type liquid crystal device in Preferred Embodiment 33. 5021is the left and right direction (lengthwise direction) of the liquidcrystal panel, 5001 is the direction of the transmissive axis of theupper polarizing plate, 5002 is the rubbing direction of the polarizingplate placed above, 5003 is the rubbing direction of the elementsubstrate placed below, and 5004 is the direction of the transmissiveaxis of the lower polarizing plate. Here, the angle 5011 formed by therubbing direction of the opposing substrate and the left and rightdirection of the liquid crystal panel is set to 45°, the angle 5012formed by the direction of the transmissive axis of the upper polarizingplate and the rubbing direction of the opposing plate is set to 90°, theangle 5013 of the twist of the liquid crystals is set to right 90°, andthe angle 5014 formed by the direction of the transmissive axis of thelower polarizing plate and the rubbing direction of the elementsubstrate is set to 90°. If placed in such a manner, when the moleculesof the center of the liquid crystal layer are voltage printed, theystand up from the side of the viewer (that is, the lower side of thedrawing), and in conjunction with the visual angle properties of the TNliquid crystals, a high-contrast display not tending toward reflectionsbecomes possible. Also, the placement whereby the transmissive axis ofthe polarizing plates are perpendicular to the rubbing directions of theadjacent substrates (so-called 0 mode) has less color variation due torelative direction compared with the parallel placement (so-called Emode), and is more desirable.

Here, a panel was fabricated whereby the multiple refractivity Δn of theliquid crystal material was made 0.084, and the Δnxd is differs bychanging the cell gap.

FIG. 51 shows the Δnxd and the reflectivity during white display. 5101is the reflectivity for each Δnxd of the preferred embodiment, and 5102is the reflectivity for each Δnxd of a comparative example. Formeasurement, it was measured such that the light is introduced uniformlyfrom all directions by using an integrating sphere. The reflectivity wastaken as 100% of a standard white plate. From FIG. 51, it can be readthat, as the Δnxd becomes larger, the visual angle becomes narrower, andthe display becomes dark because the efficiency of use of the introducedlight decreases. Consequently, in obtaining a bright display, it isdesirable that the Δnxd be small and that the fast minimum condition beused. As a matter of fact, the fast minimum condition has a deficiencythat coloration of the display is great. Therefore, in the conventionalreflective type monochrome display, a condition having a great Δnxd wasused, such as Preferred Embodiment 32. Nevertheless, the coloration canbe corrected somewhat by adjusting the color filters. In PreferredEmbodiment 33, a display whereby the white was nearly colorless andthere was substantially no change in coloration at any Δnxd by adjustingthe color filters so as to have a high transmissivity at the longwavelength end.

The highest reflectivity is demonstrated when the Δnxd is 0.42, but thereflectivity corresponding to the Δnxd in this vicinity is shown below.

Thus, a bright display can be obtained by making the Δnxd greater than0.34 μm and less than 0.52 μm.

When the Δnxd is less than 0.40 μm, a bright display can be obtained dueto the visual angle being wide, but on the other hand, the brightness inthe frontal direction is low, and under a spotlight it appears dark, soa Δnxd of 0.40 μm or more is desirable. Also, a great deal of colorationis lost on the extremes by making the Δnxd greater than 0.48 μm, so aΔnxd of 0.48 μm or less is desirable. The most desirable Δnxd is 0.42cm, where the maximum brightness can be obtained.

Preferred Embodiment 34

FIG. 52 is a drawing showing the essential components of a reflectivetype color liquid crystal device according to aspects of the presentinvention. First the configuration is explained. 5201 is the upperpolarizing plate, 5202 is phase variation film, 5203 is the uppersubstrate, 5204 is the liquid crystals, 5205 is the lower substrate,5206 is the lower polarizing plate, and 5207 is the scatteringreflective plate. On the upper substrate 5203 are provided the colorfilters 5208 and the scanning electrodes 5209, and on the lowersubstrate are provided the signal electrodes 5210. The phase variationfilm 5202 is a single-axis extended polycarbonate film, and it shows apositive phase variation. Also the color filters have the identicalspectral properties as FIG. 3 of Preferred Embodiment 2.

FIG. 53 is a drawing showing the relationships between each axis of thereflective type color liquid crystal device in Preferred Embodiment 34.5321 is the left-right direction (lengthwise direction) of the liquidcrystal panel, 5301 is the transmissive axial direction of the upperpolarizing plate, 5302 is the rubbing direction of the upper substrate,5303 is the rubbing direction of the lower substrate, 5304 is thetransmissive axial direction of the lower polarizing plate, 5305 is theextended direction of the phase variation film. Here, the angle 5311formed by the rubbing direction of the upper polarizing plate and theleft-right direction of the liquid crystal panel was set to 30°, theangle 5314 formed by the transmissive axial direction of the upperpolarizing plate and the extended direction of the phase variation filmwas set to 54°, the angle 5315 formed by the extended direction of thephase variation film and the rubbing direction of the upper polarizingplate was set to 80°, the angle 5312 of the twist of the liquid crystalswas set to left 240°, and the angle 5313 formed by the transmissiveaxial direction of the lower polarizing plate and the rubbing directionof the lower substrate was set to 43°. If placed in such a manner, whenthe molecules of the center of the liquid crystal layer are voltageprinted, they stand up from the side of the viewer (that is, the lowerside of the drawing), and in conjunction with the visual angleproperties of the TN liquid crystals, a high-contrast display nottending toward reflections becomes possible.

This is the phase variation plate compensating type STN mode proposed inthe publication of Japanese Laid-Open Patent No. 3-50249, and it ischaracterized by the point that multiplexed driving up to a 1/480 dutyratio by a simple matrix is possible. Also, despite having the samecolor filters as Preferred Embodiment 2, the aperture is high only solong as signal wires and MIM elements are not required, and an extremelybright display is possible having a reflectivity of 33% during whitedisplay. The contrast ratio was 1:8, being comparatively low, but byadding one layer of phase variation film to perform compensation, and byperforming multiple-line selective driving according to the methoddisclosed in the report of Japanese Laid-Open Patent No. 6-348230, it ispossible to display with an equal contrast and equal color as the casescomprising MIM elements.

Preferred Embodiment 35

FIG. 55 is a drawing showing the essential components of a reflectivetype color liquid crystal device according to aspects of the presentinvention. First the configuration is explained. 5501 is the upperpolarizing plate, 5502 is the phase variation film, 5503 is the uppersubstrate, 5504 is the liquid crystals, 5505 is the lower substrate,5506 is the lower polarizing plate, and 5507 is the scatteringreflective plate. On the upper substrate 5503 are provided the colorfilters 5508 and the scanning electrodes 5509, and on the lowersubstrate 5505 are provided the signal electrodes 5510. The phasevariation film 5502 is a single-axis extended polycarbonate film, and ithas a phase variation of positive 587 nm. The product Δnxd of the Δn ofthe liquid crystals and the cell gap is 0.85 μm.

FIG. 53 is a drawing showing the relationships between each axis of thereflective type color liquid crystal device in Preferred Embodiment 35.5321 is the left-right direction (lengthwise direction) of the liquidcrystal panel, 5301 is the transmissive axial direction of the upperpolarizing plate, 5302 is the rubbing direction of the upper substrate,5303 is the rubbing direction of the lower substrate, 5304 is thetransmissive axial direction of the lower polarizing plate, 5305 is theextended direction of the phase variation film. Here, the angle 5311formed by the rubbing direction of the upper polarizing plate and theleft-right direction of the liquid crystal panel was set to 30°, theangle 5314 formed by the transmissive axial direction of the upperpolarizing plate and the extended direction of the phase variation filmwas set to 38°, the angle 5315 formed by the extended direction of thephase variation film and the rubbing direction of the upper polarizingplate was set to 92°, the angle 5312 of the twist of the liquid crystalswas set to left 240°, and the angle 5313 formed by the transmissiveaxial direction of the lower polarizing plate and the rubbing directionof the lower substrate was set to 50°.

FIG. 54 is a drawing showing the spectral properties of the colorfilters of the reflective type color liquid crystal device in PreferredEmbodiment 35. The horizontal axis of FIG. 54 is the light wavelength,the vertical axis is the transmissivity, 5401 shows the spectrum of thered filter, 5402 shows the spectrum of the green filter, and 5403 showsthe spectrum of the blue filter. The properties of these color filtersare optimized such that the white balance can be taken from the spectralproperties 5411 in the off state, when excluding the color filters fromsaid liquid crystal device. Here, the green filter and the blue filterhave transmissivities of 50% or more in the 450 nm to 660 nm wavelengthrange. Also, the lowest transmissivity of the red filter for the lightof the wavelengths in the 450 nm to 660 nm range clearly is lesscompared with the blue filter and the green filter. By using such a redfilter, it is possible to display brilliantly the red color whichappeals most to the human eyes. Also, with the purpose of compensatingthe deepening of the red, the spectrum 5403 of the blue filter was madeclose to cyan.

This is the phase variation plate compensating type STN mode proposed inthe publication of Japanese Laid-Open Patent No. 3-50249, and it ischaracterized by the point that multiplexed driving up to a 1/480 dutyratio by a simple matrix is possible. However, while the conventionalphase variation compensating type STN mode can display black and white,it could only output cyan-ish white. As a matter of fact, the reflectivetype color liquid crystal device of Preferred Embodiment 35 becamecapable of displaying a white near perfect neutral more so than theconventional by having optimized the color filters. Also, despite havingused color filters having similar properties as Preferred Embodiment 9,the aperture is high only so long as signal wires and MIM elements arenot required, and an extremely bright display is possible having areflectivity of 29% during white display.

Preferred Embodiment 36

FIG. 56 is a drawing showing the essential elements of a reflective typecolor liquid crystal device according to aspects of the presentinvention. First the configuration is explained. 5601 is the upperpolarizing plate, 5602 is the opposing substrate, 5603 is the liquidcrystals, and 5604 is the element substrate. On the opposing substrate5602 are provided the color filters 5605 and the opposing electrodes(scanning wires) 5606, and on the element substrate are provided thesignal wires 5607, the pixel electrodes combined with the scatteringreflective plate 5608, and the MIM elements 5609. The pixel electrodescombined with the scattering reflective plate used had irregularitiesapplied mechanically and chemically to the surface of a metal aluminumsputtered film. Also, the color filters have the identical spectralproperties as FIG. 3 of Preferred Embodiment 2.

FIG. 57 is a drawing showing the relationships between each axis of thereflective type color liquid crystal device in Preferred Embodiment 36.5721 is the left-right direction (lengthwise direction) of the liquidcrystal panel, 5701 is the transmissive axial direction of the upperpolarizing plate, 5702 is the rubbing direction of the upper substrate,and 5703 is the rubbing direction of the lower substrate. Here, theangle 5711 formed by the rubbing direction of the upper polarizing plateand the left-right direction of the liquid crystal panel was set to 62°,the angle 5712 formed by the transmissive axial direction of the upperpolarizing plate and the rubbing direction of the upper substrate wasset to 94°, and the angle 5713 of the twist of the liquid crystals wasset to right 56°. If placed in such a manner, when the molecules of thecenter of the liquid crystal layer are voltage printed, they stand upfrom the side of the viewer (that is, the lower side of the drawing),and in conjunction with the visual angle properties of the TN liquidcrystals, a high-contrast display becomes possible.

This is the single polarizing plate type nematic liquid crystal modeproposed by the publication of Japanese Laid-Open Patent No. 3-223715,and it is characterized by the point that a scattering reflective plateis provided in the position adjacent to the liquid crystals in order tobe able to display high-contrast black and white without using a lowerpolarizing plate.

This reflective type color liquid crystal device had a reflectivity of30% during white display and a contrast ratio of 1:10, it was capable ofdisplaying the four colors, white, red, cyan, and black, the color ofthe red display was x=0.39, y=0.31, and the color of the cyan displaywas x=0.28, y=0.32. In its display there was no occurrence ofreflections, and dependence on visual angle was extremely little. Also,because the light introduced through the red filter, for example,necessarily is emitted through the red filter, a bright, high-colorpurity display was possible without the occurrence of colorcontamination.

The above preferred embodiments used MIM elements, but TFT elements alsomay be used in place of them. FIG. 58 is a drawing showing the essentialelements of the structure when having created, using TFT elements, areflective type color liquid crystal device according to aspects of thepresent invention. First the configuration is explained. 5801 is theupper polarizing plate, 5802 is the opposing substrate, 5803 is theliquid crystals, and 5804 is the element substrate. On the opposingsubstrate 5802 are provided the color filters 5805 and the opposingelectrodes (common electrodes) 5806, and on the element substrate 5804are provided gate signal wires 5807, source signal wires 5808, the TFTelements 5809, and the pixel electrodes combined with the scatteringreflective plate 5810. In the case of MIM elements, metallic wiring onlyran in the up and down directions, but with TFT elements, because themetallic wiring runs up and down as well as left and right, the aperturedecreases. Fortunately, in this Preferred Embodiment 37 there is no needfor a lower polarizing plate. Thus, when using TFT elements, it isdesirable to provide an insulating film on the element and signal wirelayers, on top of that to provide anew a reflective plate combined withpixel electrodes, and to take a method to connect the two via a contacthole.

Preferred Embodiment 37

Preferred Embodiment 37 relates to a reflective type color liquidcrystal device according to aspects of the present invention, but firstwill be introduced six examples of reflective type monochrome liquidcrystal devices. Any of these can be used as a reflective type colorliquid crystal device by adding color filters.

FIRST EXAMPLE

FIG. 59 is a cross section drawing of a reflective type liquid crystaldevice in the first example. First the configuration is explained. 5901is the scattering plate, 5902 is the upper polarizing plate, 5903 is theupper substrate, 5904 is the upper electrodes, 5905 is the liquidcrystals, 5906 is the lower electrodes, 5907 is the lower substrate,5908 is the lower polarizing plate, and 5909 is the mirror reflectiveplate. The liquid crystals 5905 are twisted 90 degrees in the cells, andare TN mode, whereby the absorption axes of the polarizing plates 5902and 5908 coincide with the lag phase axes of the liquid crystals 5 ofthe adjacent boundaries. The product Δnxd of the thickness d of theliquid crystals 5905 and the multiple refractivity Δn is 0.48 μm.

The reflective type liquid crystal device above had a brightness of 25%and a contrast of 1:15 during white display in a room in the normal linedirection of the substrates, and a brightness of 45% and a contrast of1:12 in the regular reflective direction of a ceiling lamp. Even in theregular reflective direction, there is no reflection of the ceiling lampdue to the effect of the back scattering of the scattering plate, and ahigh contrast can be obtained.

Thus, because the light of the regular reflective direction can be usedeffectively while preserving a sufficient contrast, a very brightdisplay can be obtained.

SECOND EXAMPLE

FIG. 60 is a cross section drawing of reflective type liquid crystaldevices No. 1 to No. 3 in the second example. 6001 is the scatteringplate, 6002 is the upper polarizing plate, 6003 is the upper substrate,6004 is the upper electrodes, 6005 is the liquid crystals, 6006 is thelower electrodes, 6007 is the lower substrate, and 6008 is the mirrorreflective plate.

FIG. 61 shows the axial directions of the polarizing plates, and thelike, of the reflective type liquid crystal devices No. 1 to No. 3 inthe second example. 6101 is the transmissive axial direction of theupper polarizing plate 6002, 6103 is the rubbing direction of the uppersubstrate 6003, 6103 is the rubbing direction of the lower substrate6007, 6104 is the angle θ1 of the transmissive axial direction 6101 ofthe upper polarizing plate 6002 with the horizontal level, 6105 is theangle θ2 of the rubbing direction 6102 of the upper substrate 6003 withthe horizontal level, and 6106 is the angle θ3 of the rubbing direction6103 of the lower substrate 6007 with the horizontal level. The anglesare positive counterclockwise, and are shown from −180° to 180°.

FIG. 62 is a cross section drawing of reflective type liquid crystaldevices No. 4 to No. 6 in the second example. 6201 is the scatteringplate, 6202 is the upper polarizing plate, 6203 is the phase variationplate, 6204 is the upper substrate, 6205 is the upper electrodes, 6206is the liquid crystals, 6207 is the lower electrodes, 6208 is the lowersubstrate, and 6209 is the mirror reflective plate.

FIG. 63 shows the axial directions of the polarizing plates, and thelike, of the reflective type liquid crystal devices No. 4 to No. 6 inthe second example. 6301 is the transmissive axial direction of theupper polarizing plate 6202, 6302 is the lag phase axial direction ofthe phase variation plate 6203, 6303 is the rubbing direction of theupper substrate 6204, 6304 is the rubbing direction of the lowersubstrate 6208, 6305 is the angle B1 of the transmissive axial direction6301 of the upper polarizing plate 6202 with the horizontal level, 6306is the angle θ2 of the rubbing direction 6303 of the upper substrate6204 with the horizontal level, 6307 is the angle θ3 of the rubbingdirection 6304 of the lower substrate 6208 with the horizontal level,and 6308 is the angle θ4 of the lag phase axial direction 6302 of thephase variation plate 6203.

These angular conditions and the values of the Δnxd of the liquidcrystal cells and the phase variation of the phase variation plates areshown in the table below. The units of the Δnxd and the phase variationare in μm.

These properties are shown in the table below.

A sufficient contrast and bright display can be obtained in the samemanner as the first example.

COMPARATIVE EXAMPLE OF THE FIRST EXAMPLE AND THE SECOND EXAMPLE

FIG. 64 shows a cross section of the reflective type liquid crystaldevice in a comparative example. 6401 is the upper polarizing plate,6402 is the upper substrate, 6403 is the upper electrodes, 6404 is theliquid crystals, 6405 is the lower electrodes, 6406 is the lowersubstrate, 6407 is the lower polarizing plate, and 6408 is thescattering reflective plate. The liquid crystals 6404 are twisted 90degrees in the cells in the same manner as the first example, and are TNmode, whereby the absorption axes of the polarizing plates 6401 and 6407coincide with the lag phase axes of the liquid crystals 5 of theadjacent boundaries. The product Δnxd of the thickness d of the liquidcrystals 6404 and the multiple refractivity Δn is 0.48 μm.

The reflective type liquid crystal device of the above configuration hada brightness of 28% and a contrast of 1:15 during white display in aroom in the normal line direction of the substrates, but in the regularreflective direction of a ceiling lamp, the brightness of the whitedisplay became 62% and the contrast became 1:2 due to the reflection ofthe ceiling light, and it could not stand to practical use.

THIRD EXAMPLE

FIG. 65 is a drawing showing the properties of the scattering plate of areflective type liquid crystal device in the third example. In FIG. 65,6501 is the scattering plate, 6502 is the introduced light, 6503 is theregularly reflected light, and 6504 is a 10° cone centered on theregularly reflected light 6503. The scattering plate 6501 of the thirdexample has 5% of the introduced light be scattered in the 10° cone.

A scattering plate having the above properties was obtained, as inShingaku Giho EID95-146, by creating forward scattering by mixing ofparticles having refractivities different from the medium, and adjustingthe back scattering by providing minute irregularities on the surface.If this scattered light is greater than 10%, reflection of the lightsource becomes greater and the contrast decreases. Conversely, if it isless than 0.5%, fading of the display becomes too much.

Also, the configuration of the present preferred embodiment is identicalto the configuration shown in FIG. 59 of the first example, the liquidcrystals 5905 are twisted 90 degrees in the cells, and are TN mode,whereby the absorption axes of the polarizing plates 5902 and 5908coincide with the lag phase axes of the liquid crystals 5905 of theadjacent boundaries. The product Δnxd of the thickness d of the liquidcrystals 5905 and the multiple refractivity Δn is 0.48 μm.

The reflective type liquid crystal device above had a brightness of 26%and a contrast of 1:15 during white display in a room in the normal linedirection of the substrates, and a brightness of 43% and a contrast of1:13 in the regular reflective direction of a ceiling lamp.

FOURTH EXAMPLE

The scattering plate shown in FIG. 65 of the third example was appliedto the configuration of FIG. 60 and FIG. 62 of the second example.

The directions of all the axes and the Δnxd and phase variation of theliquid crystals shown in FIG. 61 and FIG. 63 were set identically to thesecond example. The properties are shown in the table below.

A sufficient contrast and bright display can be obtained in the samemanner as Preferred Embodiment 1.

FIFTH EXAMPLE

FIG. 66 is a cross section drawing of a reflective type liquid crystaldevice in the fifth example. First the configuration is explained. 6601is the scattering plate, 6602 is the upper polarizing plate, 6603 is theupper substrate, 6604 is the upper electrodes, 6605 is the liquidcrystals, 6606 is the lower polarizing plate, 6607 is the lowerelectrodes and mirror reflective plate, and 6608 is the lower substrate.The liquid crystals 6605 are twisted 90 degrees in the cells, and are TNmode, whereby the absorption axes of the polarizing plates 6602 and 6606coincide with the lag phase axes of the liquid crystals 5 of theadjacent boundaries. The product Δnxd of the thickness d of the liquidcrystals 6605 and the multiple refractivity Δn is 0.48 μm. On the lowerelectrodes was vapor deposited aluminum, and the polarizing plates wereobtained by painting and orienting a crystalline polymer solutioncontaining a black dichromatic dye on a polyimide orientation film. Forthe scattering plate, the same things as the third example were used.

The reflective type liquid crystal device above had a brightness of 28%and a contrast of 1:18 during white display in a room in the normal linedirection of the substrates, and a brightness of 44% and a contrast of1:16 in the regular reflective direction of a ceiling lamp.

SIXTH EXAMPLE

FIG. 67 is a cross section drawing of a reflective type liquid crystaldevices No. 1 to No. 3 in the sixth example. 6701 is the scatteringplate, 6702 is the upper polarizing plate, 6703 is the upper substrate,6704 is the upper electrodes, 6705 is the liquid crystals, 6706 is thelower electrodes and mirror reflective plate, and 6707 is the lowersubstrate.

FIG. 61 shows the axial directions of the polarizing plates, and thelike, of the reflective type liquid crystal devices No. 1 to No. 3 inthe sixth example. 6101 is the transmissive axial direction of the upperpolarizing plate 6002, 6103 is the rubbing direction of the uppersubstrate 6003, 6103 is the rubbing direction of the lower substrate6007, 6104 is the angle θ1 of the transmissive axial direction 6101 ofthe upper polarizing plate 6002 with the horizontal level, 6105 is theangle θ2 of the rubbing direction 6102 of the upper substrate 6003 withthe horizontal level, and 6106 is the angle θ3 of the rubbing direction6103 of the lower substrate 6007 with the horizontal level.

FIG. 68 is a cross section drawing of reflective type liquid crystaldevices No. 4 to No. 6 in the sixth example. 6801 is the scatteringplate, 6802 is the upper polarizing plate, 6803 is the phase variationplate, 6804 is the upper substrate, 6805 is the upper electrodes, 6806is the liquid crystals, 6807 is the lower electrodes and mirrorreflective plate, and 6808 is the lower substrate.

FIG. 63 shows the axial directions of the polarizing plates, and thelike, of the reflective type liquid crystal devices No. 4 to No. 6 inthe sixth example. 6301 is the transmissive axial direction of the upperpolarizing plate 6202, 6302 is the lag phase axial direction of thephase variation plate 6203, 6303 is the rubbing direction of the uppersubstrate 6204, 6304 is the rubbing direction of the lower substrate6208, 6305 is the angle θ1 of the transmissive axial direction 6301 ofthe upper polarizing plate 6202 with the horizontal level, 6306 is theangle θ2 of the rubbing direction 6303 of the upper substrate 6204 withthe horizontal level, 6307 is the angle θ3 of the rubbing direction 6304of the lower-substrate 6208 with the horizontal level, and 6308 is theangle θ4 of the lag phase axial direction 6302 of the phase variationplate 6203.

The conditions of the angles and the values of the Δnxd of the liquidcrystal cells and the phase variation of the phase variation plates arethe same as Table 4 shown in the second example. Also, for thescattering plate, the same things as the third example were used.

The properties of the reflective type liquid crystal device of the aboveconfiguration are shown in the table below.

A sufficient contrast and bright display can be obtained for all ofthese.

All of the six reflective type monochrome liquid crystal display devicesshown above can be used as reflective type color liquid crystal displaydevices by adding color filters, but next is shown one example of them.

FIG. 69 is a drawing showing the essential components of a reflectivetype color liquid crystal display according to aspects of the presentinvention. 6901 is the scattering plate, 6902 is the upper polarizingplate, 6903 is the phase variation plate, 6904 is the upper substrate,6905 is the liquid crystals, 6906 is the lower substrate, 6907 is theopposing electrodes (scanning wires), 6908 is the signal wires, 6909 isthe pixel electrodes and mirror reflective plate, 6910 is the MIMelements, and 6911 is the color filters. The intervals between pixel andpixel were perpendicular to the signal wires and were 160 cm in bothparallel directions, the width of the signal wires was 10 μm, the gapsbetween the signal wires and the pixel electrodes were 10 μm, and theintervals between adjacent pixel electrode and pixel electrode were 10μm.

FIG. 63 shows the axial directions of the polarizing plates, and thelike. 6301 is the transmissive axial direction of the upper polarizingplate 6202, 6302 is the lag phase axial direction of the phase variationplate 6203, 6303 is the rubbing direction of the upper substrate 6204,6304 is the rubbing direction of the lower substrate 6208, 6305 is theangle θ1 of the transmissive axial direction 6301 of the upperpolarizing plate 6202 with the horizontal level, 6306 is the angle θ2 ofthe rubbing direction 6303 of the upper substrate 6204 with thehorizontal level, 6307 is the angle θ3 of the rubbing direction 6304 ofthe lower substrate 6208 with the horizontal level, and 6308 is theangle θ4 of the lag phase axial direction 6302 of the phase variationplate 6203.

The Δnxd of the liquid crystals 6905 was set to 0.33 μm, θ1 was set to−82°, θ2 was set to −74°, θ3 was set to 74°, θ4 was set to 9°, the phasevariation of the phase variation plate 6903 was set to 0.31 μm, andorientation processing was applied on the signal wires 6908 in the samemanner as on the mirror reflective plate 6909.

For the scattering plate was used the same thing as the scattering plateof the third example. Also, for the color filters were used cyan (C inthe drawing) and red (R in the drawing) color filters having an averagetransmissivity of 75%.

The reflective type liquid crystal devices of the above configurationhad a brightness of 30% and a contrast of 1:15 during white display in aroom in the normal line direction of the substrates, and a brightness of51% and a contrast of 1:12 in the regular reflective direction of aceiling lamp. For all of them the display colors were x=0.39, y=0.32 forred, and x=0.28, y=0.31 for cyan. The colors can be recognizedsufficiently, and they are bright colors.

Preferred Embodiment 38

Preferred Embodiment 38 relates to a reflective type color liquidcrystal device according to aspects of the present invention, but firstwill be introduced two examples of reflective type monochrome liquidcrystal devices. Either of these can be used as a reflective type colorliquid crystal device by adding color filters.

FIRST EXAMPLE

FIG. 70 is a drawing showing the essential components of the reflectivetype color liquid crystal display of the first example. 7001 is thescattering plate, 7002 is the upper polarizing plate, 7003 is the uppersubstrate, 7004 is the liquid crystals, 7005 is the lower substrate,7006 is the lower polarizing plate, 7007 is the mirror reflective plate,7008 is the opposing electrodes (scanning wires), and 7009 is the signalwires, 7010 is the pixel electrodes, and 7011 is the MIM elements. Theliquid crystals 7004 are twisted 90 degrees in the cells, and are TNmode, whereby the absorption axes of the polarizing plates 7002 and 7006coincide with the lag phase axes of the liquid crystals 7004 of theadjacent boundaries. The product Δnxd of the thickness d of the liquidcrystals 7004 and the multiple refractivity Δn is 0.48 μm. For thescattering plate was used the same thing as the scattering plate of thethird example.

The intervals between pixel and pixel were perpendicular to the signalwires and were 160 μm in both parallel directions, the width of thesignal wires was 10 cm, the gaps between the signal wires and the pixelelectrodes were 10 μm, and the intervals between adjacent pixelelectrode and pixel electrode were 10 μm.

In the reflective type liquid crystal device of the above configuration,when the liquid crystals have been arranged by applying rubbingprocessing also to the areas other than the pixels, being the signalwires 7009 and the opposing electrodes 7008, in the same manner as thepixel electrodes 7010, it had a brightness of 23% and a contrast of 1:14during white display in a room in the normal line direction of thesubstrates, and a brightness of 43% and a contrast of 1:11 in theregular reflective direction of a ceiling lamp.

By the way, because the paintability on metallic electrodes differs fromthat of the ITO of the pixel electrodes, even when painting anorientation film, it often comes off. In such a case, that is, whenorientation processing was not applied on the signal wires 7009, it hada brightness of 19% and a contrast of 1:14 during white display in aroom in the normal line direction of the substrates, and a brightness of40% and a contrast of 1:11 in the regular reflective direction of aceiling lamp.

In either case, a high contrast and bright display could be obtained,and a brighter display could be obtained by orientation processing onthe metallic wiring.

SECOND EXAMPLE

FIG. 71 is a drawing showing the essential components of the reflectivetype liquid crystal devices No. 1 and No. 3 in the second example. 7101is the scattering plate, 7102 is the upper polarizing plate, 7103 is theupper substrate, 7104 is the liquid crystals, 7105 is the lowersubstrate, 7106 is the mirror reflective plate, 7107 is the opposingelectrodes (scanning wires), 7108 is the signal wires, 7109 is the pixelelectrodes, and 7110 is the MIM elements. The intervals between pixeland pixel were perpendicular to the signal wires and were 160 μm in bothparallel directions, the width of the signal wires was 10 μm, the gapsbetween the signal wires and the pixel electrodes were 10 μm, and theintervals between adjacent pixel electrode and pixel electrode were 10μm.

FIG. 61 shows the axial directions of the polarizing plates, and thelike, of the reflective type liquid crystal devices No. 1 to No. 3 inthe second example. 6101 is the transmissive axial direction of theupper polarizing plate 6002, 6103 is the rubbing direction of the uppersubstrate 6003, 6103 is the rubbing direction of the lower substrate6007, 6104 is the angle θ1 of the transmissive axial direction 6101 ofthe upper polarizing plate 6002 with the horizontal level, 6105 is theangle θ2 of the rubbing direction 6102 of the upper substrate 6003 withthe horizontal level, and 6106 is the angle θ3 of the rubbing direction6103 of the lower substrate 6007 with the horizontal level.

FIG. 72 is a drawing showing the essential components of the reflectivetype liquid crystal devices No. 2 and No. 4 in the second example. 7201is the scattering plate, 7202 is the phase variation plate, 7203 is theupper polarizing plate, 7204 is the upper substrate, 7205 is the liquidcrystals, 7206 is the lower substrate, 7207 is the mirror reflectiveplate, 7208 is the opposing electrodes (scanning wires), 7209 is thesignal wires, 7210 is the pixel electrodes, and 7211 is the MIMelements. The intervals between pixel and pixel were perpendicular tothe signal wires and were 160 μm in both parallel directions, the widthof the signal wires was 10 μm, the gaps between the signal wires and thepixel electrodes were 10 μm, and the intervals between adjacent pixelelectrode and pixel electrode were 10 μm.

FIG. 63 shows the axial directions of the polarizing plates, and thelike, of the reflective type liquid crystal devices No. 4 to No. 6 inthe second example. 6301 is the transmissive axial direction of theupper polarizing plate 6202, 6302 is the lag phase axial direction ofthe phase variation plate 6203, 6303 is the rubbing direction of theupper substrate 6204, 6304 is the rubbing direction of the lowersubstrate 6208, 6305 is the angle θ1 of the transmissive axial direction6301 of the upper polarizing plate 6202 with the horizontal level, 6306is the angle θ2 of the rubbing direction 6303 of the upper substrate6204 with the horizontal level, 6307 is the angle θ3 of the rubbingdirection 6304 of the lower substrate 6208 with the horizontal level,and 6308 is the angle θ4 of the lag phase axial direction 6302 of thephase variation plate 6203.

For the scattering plate was used the same thing as the scattering plateof the third example of Preferred Embodiment 37.

In the reflective type liquid crystal device of the above configuration,No. 1 and No. 2 had orientation processing applied also to the areasother than the pixels, and No. 3 and No. 4 had orientation processingonly to the pixels.

The Δnxd of the liquid crystals 7205, the angles of the polarizingplates, and the like, and the phase variation of the phase variationplate are shown in the table below.

Also, their properties are shown in the table below.

In both examples, a high contrast and bright display could be obtained,and a brighter display could be obtained by orientation processing inthe areas other than the pixels.

Preferred Embodiment 39

Preferred Embodiment 39 relates to a reflective type color liquidcrystal device according to aspects of the present invention, but firstwill be introduced an example of a reflective type monochrome liquidcrystal device. This can be used as a reflective type color liquidcrystal device by adding color filters.

FIG. 59 is a cross section drawing of reflective type liquid crystaldevices No. 1 and No. 2 according to aspects of the present invention.First the configuration is explained. 5901 is the scattering plate, 5902is the upper polarizing plate, 5903 is the upper substrate, 5904 is theupper electrodes, 5905 is the liquid crystals, 5906 is the lowerelectrodes, 5907 is the lower substrate, 5908 is the lower polarizingplate, and 5909 is the mirror reflective plate. The liquid crystals 5905are twisted 90 degrees in the cells, and are TN mode, whereby No. 1 hasthe absorption axes of the polarizing plates 5902 and 5908 coincide withthe lag phase axes of the liquid crystals 5905 of the adjacentboundaries, and No. 2 has the absorption axis of the polarizing plate5902 and the absorption axis of the polarizing plate 5908 coincide withthe lag phase axes of the liquid crystals 5905 of the respectivelyadjacent boundaries. The product Δnxd of the thickness d of the liquidcrystals 5905 and the multiple refractivity Δn is 0.48 μm.

For the scattering plate was used the same thing as the scattering plateof the third example of Preferred Embodiment 37.

FIG. 73 is a drawing showing the voltage transmissivity properties of areflective type liquid crystal device according to aspects of thepresent invention. Here, 7301 is the manner of the change oftransmissivity in relation to voltage of No. 1, and 7302 is the mannerof the change of transmissivity in relation to voltage of No. 2. No. 1is normally white, and No. 2 is a normally black display.

For the reflective type liquid crystal devices of the aboveconfiguration, No. 1 had a brightness of 25% and a contrast of 1:15during white display in a room in the normal line direction of thesubstrates, and a brightness of 45% and a contrast of 1:12 in theregular reflective direction of a ceiling lamp. No. 2 had a brightnessof 23% and a contrast of 1:15 during white display in a room in thenormal line direction of the substrates, and a brightness of 42% and acontrast of 1:13 in the regular reflective direction of a ceiling lamp.

Both could obtain a sufficient contrast and bright display, but thenormally white one could obtain a brighter display. This is because theareas outside the pixels contribute to the brightness, and also becauseit has visual angle properties whereby the light introduced fromdiagonal directions is easily transmitted.

Preferred Embodiment 40

When performing display with a reflective type color liquid crystaldevice in Preferred Embodiments 1 to 39 above, there occurs a problemwhich did not exist with the conventional transmissive type color liquidcrystal device. That is the fact that it does not show enough color witha single dot, and in order to display color, it is necessary to displaythe same color across an area of a certain width. The causes of this arethat the colors of the color filters are pale, there is a distancebetween the liquid crystal layer and the reflective plate (exceptingPreferred Embodiments 36 to 39), and the colors of the neighboring dotsmix easily.

Consequently, rather than a method of use such as displaying redcharacters on a white background, a method of use such as displayingblack characters on a white background and making a part of thebackground red, that is, a method of use such as a marker, is moreappropriate. Nevertheless, the fact that it does not show enough colorwith a single pixel means also that, conversely, while it is a colorliquid crystal device, it can display black and white easily.

Preferred Embodiment 40 is a reflective type color liquid crystal deviceaccording to aspects of the invention, and is characterized by one pixelbeing composed of one dot. A pixel is the minimum unit capable ofrealizing the function necessary for display, and in the usual colorliquid crystal device, one pixel is composed of a total of three dots,each dot being red, green, or blue. Consequently, in order to perform a480×640 VGA display, 480×640×3 dots was necessary. When using two colorsof color filters, being cyan and red, 480×640×2 dots was necessary.However, Preferred Embodiment 40 can perform VGA display with 480×640pixels in a color liquid crystal device.

The configuration of Preferred Embodiment 40 is identical to, forexample, Preferred Embodiment 5. Only the following efforts are madewhen performing display. An example is shown in FIG. 74, so it isexplained following this drawing. Here, 16×48 pixels are illustrated.(a) is a drawing showing the arrangement of the color filters, and red(shown as “R”) and cyan (shown as “C”) are arranged in a mosaic pattern.Also, (b) and (c) are drawings showing the distribution of on dots andoff dots. Because the on dots are dark, they are shown with hatching.The (b) display turns on the pattern of “LCD” ignoring the arrangementof the color filters, but as described before, because this reflectivetype color liquid crystal device does not show colors sufficiently witha single dot, “LCD” appears displayed in black on a white background.Consequently, black and white display is possible at the resolution ofVGA. Meanwhile, because the (c) display turned on only the cyan-coloreddots of the background of (b), “LCD” appears displayed in black on a redbackground. When displaying in this manner the same color across an areaof ten dots or wider than that, it becomes possible to display colors.

In addition to such a method of use as a marker, for example, whendisplaying map information, it becomes possible to color only thespecified routes if the widths of the roads are several dots. Also,because the icons on a PC screen are of a certain extent of area, theircolor display is possible.

Preferred Embodiment 41

A reflective type color liquid crystal device of Preferred Embodiments 1to 40 above was selected as the display of an electronic apparatus.

FIG. 75 is a drawing showing one example of an electronic apparatusaccording to aspects of the invention. This is a so-called PDA (PersonalDigital Assistant), and it is a type of portable information terminal.7501 is the reflective type color liquid crystal device, and on itsfront is attached a tablet for pen input. For the PDA display, aconventional reflective type monochrome liquid crystal device or atransmissive type color liquid crystal device was used. By exchangingthese with a reflective type color liquid crystal device, it has themerit that the amount of information by color display increases by leapscompared with the former. Also, it has the merits of extension ofbattery life and miniaturization.

FIG. 76 is a drawing showing an example of an electronic apparatusaccording to aspects of the invention. This is a so-called digital stillcamera. 7601 is the reflective type color liquid crystal device, and itis installed such that its angle can be changed in relation to the body.Also, not illustrated, there is a lens inside this reflective type colorliquid crystal device attachment. For the display of a digital stillcamera, a conventional transmissive type color liquid crystal device wasused. By replacing this with a reflective type color liquid crystaldevice, not to mention the extension of battery life andminiaturization, the visual recognition under direct sunlight wasimproved dramatically. The reason is that, because a transmissive typecolor liquid crystal device is limited in the brightness of thebacklights, it becomes hard to see when the surface reflection underdirect sunlight becomes greater, but for a reflective type color liquidcrystal device, the display also becomes brighter as the ambient lightbecomes brighter. Also because this ambient light is used efficiently,it is effective to be installed such that the angle of the liquidcrystal device can be changed.

A reflective type color liquid crystal device can be applied to variouselectronic apparatuses emphasizing portability in addition to theelectronic apparatuses mentioned above, such as palmtop PCs andsub-notebook PCs, notebook PCs, handy terminals, camcorders, liquidcrystal TVs, game machines, electronic notebooks, portable telephones,and pagers.

Utility in the Industry

As described above, according to the present invention, by having a TNor STN liquid crystal display mode using polarizing plates, and bycombining this with bright color filters, it is possible to provide areflective type color liquid crystal device capable of displaying colorsbrighter and more brilliantly than the conventional, and also it ispossible to provide electronic apparatuses using this. TABLE 1Difference in Levels Between Color Filters And Transmissive Layer 1.0 μm0.5 μm 0.3 μm 0.1 μm 0.05 μm Image Quality x ◯ ◯ ⊚ ⊚ Contrast 1:5.21:10.4 1:14.0 1:15.4 1:19.2Image Quality: 0 . . . very bad, 1 . . . bad, 2 . . . good, 3 . . . verygood.

TABLE 2 Transmissive Layer None Acryl Polyimide Polyvinyl AlcoholContrast 1:8.1 1:20.2 1:19.6 1:17.9 Image Quality x ⊚ ⊚ ⊚Image Quality: 0 . . . very bad, 1 . . . bad, 2 . . . good, 3 . . . verygood.

TABLE 3 Δnxd (μm) Reflectivity (%) Comparative Example 0.30 20.8 0.3222.2 0.34 23.2 Preferred Embodiment 0.36 23.7 0.38 24.1 0.40 24.3 0.4224.3 0.44 24.2 0.46 24.0 0.48 23.9 0.50 23.5 Comparative Example 0.5223.2 0.54 22.9 0.56 22.7

TABLE 4 Phase Twist No. Δnxd θ 1 θ 2 θ 3 θ 4 Retardation Orientation 10.40 32.5 −67.5 67.5 Right 45° 2 0.64 32.0 −68.0 68.0 Right 45° 3 0.80−22.5 −37.5 37.5 Left 255° 4 0.33 −82.0 −74.0 74.0 9.0 0.31 Right 32° 50.45 27.5 −67.5 67.5 27.5 0.65 Right 45° 6 0.70 −8.0 −30.0 30.0 70.00.35 Left 240°

TABLE 5 Normal Line Direction Direction of Of Substrate MirrorReflection No. Reflectivity (%) Contrast Reflectivity (%) Contrast 1 291:12 50 1:10 2 27 1:13 48 1:11 3 27 1:06 49 1:04 4 30 1:15 52 1:12 5 271:15 48 1:12 6 29 1:08 50 1:06

TABLE 6 Normal Line Direction Direction of Of Substrate MirrorReflection No. Reflectivity (%) Contrast Reflectivity (%) Contrast 1 301:12 49 1:10 2 28 1:13 47 1:11 3 28 1:06 47 1:04 4 31 1:15 51 1:12 5 281:15 46 1:12 6 30 1:08 49 1:06

TABLE 7 Normal Line Direction Direction of Of Substrate MirrorReflection No. Reflectivity (%) Contrast Reflectivity (%) Contrast 1 321:14 54 1:11 2 29 1:15 50 1:13 3 30 1:08 51 1:06 4 35 1:19 55 1:15 5 301:19 51 1:15 6 31 1:10 52 1:08

TABLE 8 Phase Twist No. Δnxd θ 1 θ 2 θ 3 θ 4 Retardation Orientation 1,3 0.40 32.5 −67.5 67.5 Right 45° 2, 4 0.33 −82.0 −74.0 74.0 9.0 0.31Right 32°

TABLE 9 Normal Line Direction of Orientation Direction of SubstanceMirror Reflection Processing Reflectivity Reflectivity Outside No. (%)Contrast (%) Contrast Pixel Area 1 29 1:12 50 1:10 Yes 2 27 1:13 48 1:11Yes 3 27 1:06 49 1:04 No 4 29 1:08 50 1:06 No

1. A color liquid crystal device comprising: a pair of opposingsubstrates; a liquid crystal layer between the pair of opposingsubstrates; a plurality of dots capable of independently applyingvoltage to the liquid crystal layer, each dot having a dot area thatincludes a first section and a second section; a color filter arrangedin the first section of at least one of the dots; and a substantiallytransparent area arranged in the at least one of the dots in the secondsection where the color filter is not arranged.
 2. The color liquidcrystal device according to claim 1, the substantially transparent areabeing a layer including acryl.
 3. The color liquid crystal deviceaccording to claim 1, the substantially transparent area being a layerincluding polyimide.
 4. The color liquid crystal device according toclaim 1, the substantially transparent area extending across an areabetween adjacent dots.
 5. The color liquid crystal device according toclaim 1, the substantially transparent area extending from one side ofthe at least one of the dots to the other side of the one of the dots.6. The color liquid crystal device according to claim 1, the pluralityof dots comprising a display face, the color filter including aplurality of color filters in a one-to-one correspondence with the dots,a surface area ratio of all the color filters to the entire display facebeing 15% or more.
 7. The color liquid crystal device according to claim6, the surface area ratio of all the color filters to the entire displayface being 25% or more.
 8. The color liquid crystal device according toclaim 6, the surface area ratio of all the color filters to the entiredisplay face being 45% or more.